Abiotic Anti-VEGF Nanoparticle

ABSTRACT

The present invention relates generally to compositions and methods comprising abiotic, synthetic polymers with affinity and specificity to proteins. The synthetic polymers are an improvement over biological agents by providing a simpler, less expensive, and customizable platform for binding to proteins. In one embodiment, the compositions and methods relate to synthetic polymers with affinity and specificity to vascular endothelial growth factor (VEGF). In one embodiment, the compositions are useful for treating diseases and disorders related to the overexpression of VEGF. In one embodiment, the compositions are useful for treating cancer. In one embodiment, the compositions are useful for detecting VEGF levels from biological samples. In one embodiment, the compositions are useful for detecting overexpression of VEGF from biological samples. In one embodiment, the compositions are used to diagnose cancer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase application filed under 35U.S.C. § 371 claiming benefit to International Patent Application No.PCT/US17/48528, filed Aug. 25, 2017, which is entitled to priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/379,584, filed Aug. 25, 2016, the contents of which are incorporatedby reference herein in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under grant numberDMR-1308363 awarded by the National Science Foundation. The governmenthas certain rights in the invention.

BACKGROUND OF THE INVENTION

Protein affinity reagents are widely used in basic research, industrialprocesses and clinical applications for isolation of individualproteins, for analytical or diagnostic purposes, and for their effect onbiological systems by modulating the function of the target protein formechanistic research or for therapeutic intervention. Antibodies ortheir fragments are the most common protein affinity reagents (Hardiman,G., P Natl Acad Sci USA (2012) 109:18245-18246). In addition, there arenow a number of new technologies that are being developed to generateaffinity reagents including antibody-like molecules that utilize novelprotein scaffolds (Dubel, S. et al., Trends Biotechnol (2010)28:333-339), oligomers (e.g., RNA and DNA aptamers) (Lollo, B. et al.,Proteomics (2014), 14:638-644), native or synthesized amino acidpolypeptides (Cobaugh, C. W. et al., J Mol Biol (2008) 378:622-633), andvarious hybrids of these forms (Marx, V., Nat Methods (2013)10:829-833). Despite the variety of approaches for generating biologicalaffinity reagents, current limitations including time needed for theirdiscovery, development and production, reagent cost, and robustnessprovide strong motivation to explore non-biological alternatives.

Affinity reagents such as antibodies and related biologicalmacromolecules “recognize” protein surfaces with combinations of 22proteinogenic amino acids. The affinity is due to the sum total ofcomplementary non-covalent interactions over surfaces that often exceed1500 Å² and involve at least 20-30 amino acid contacts from eachpartner. Unlike well-defined enzyme active sites that can be targeted bysmall organic molecules (i.e., enzyme inhibitors), protein surfaces aremildly undulating and relatively featureless. An effectivenon-biological synthetic protein affinity reagent should engage aprotein surface with multiple contacts over a substantial surface area,an attribute that challenges discovery of small organic molecularinhibitors of protein-protein complex formation (Arkin, M. R. et al.,Nat. Rev. Drug Discov. (2004) 3:301-317).

Synthetic polymers have many features that make them attractivecandidates as protein affinity reagents. They can be designed to belarge and flexible, properties that allow them to map onto significantportions of a protein surface. In addition, they are relatively simpleand inexpensive to produce and can be prepared rapidly on a large scalein the chemistry laboratory. Since their synthesis does not requireliving organisms, biological contamination is avoided. Organic polymersare robust and can function under a variety of physiological andnonphysiological conditions. A broad range of chemical functionality isavailable to synthetic polymers permitting opportunities for optimizingaffinity. Furthermore the size, physical properties, andbiomacromolecule affinity of many polymers can be influenced by externalstimuli (temperature, pH, ionic strength) providing an extra dimensionof control (Klinger, D. et al., Polymer (2012) 53:5209-5231; Schild, H.G., Progress in Polymer Science (1992) 17:163-249).

However, since synthetic polymers are prepared by a kinetically drivenfree radical polymerization, the sequence of functional monomers is notcontrolled. The absence of sequence control may be compensated to somedegree by their conformational promiscuity. This would allowoptimization of complementary interactions with protein surfaces by aninduced fit, a process that finds many analogies in biology (Uversky, V.N. et al., Annu Rev Biophys (2008) 37:215-246; Rogers, J. M. et al., J.Am. Chem. Soc. (2014) 136:5197-5200). Compositional optimization permits“focusing” on a particular biomacromolecule target by adjusting the NPschemical constituents. A lightly cross-linked network polymer presents3-dimensional arrays of linear polymer segments that can serve as bothcontinuous and discontinuous recognition elements for binding proteinsurfaces. Nevertheless, the advantages of synthetic polymers must betempered by the fact that the polymers are not pure substances; theiraffinity, for example, is the average of the ensemble of all thepolymers in the measurement. In this regard, they may be viewed asprimitive polyclonals. Although some success in refining and focusingthat distribution has been made (Hoshino, Y. et al., J. Am. Chem. Soc.(2010) 132:13648-13650), challenges remain to demonstrate the ability toproduce a polymer NP with affinity to provide a sufficient andconsistent level of function.

In recent work, a small but growing body of evidence suggests thatsynthetic linear polymers (Christman, K. L. et al., J. Am. Chem. Soc.(2008) 130:16585-16591; Oh, Y. I. et al., Angew. Chem. Int. Ed. (2013)52:11796-11799; Nguyen, T. H. et al. Nat Chem (2013) 5:221-227),dendritic polymers (Dernedde, J. et al. P Natl Acad Sci USA (2010)107:19679-19684), and polymer nanoparticles (NPs) can be engineered toexhibit strong affinity for a range of target peptides (Hoshino, Y. etal. P Natl Acad Sci USA (2012) 109:33-38; Yoshimatsu, K. et al., Natprotoc (2015) 10:595-604; Koch, S. J. et al., Angew. Chem. Int. Ed.(2006) 45:6352-6355), proteins (Lee, S. H. et al., J. Am. Chem. Soc.(2012) 134:15765-15772; Yoshimatsu, K. et al., Angew. Chem. Int. Ed.(2012) 51:2405-2408), and polysaccharides (Lee, S. H. et al., J. Am.Chem. Soc. (2012) 134:15765-15772). Indeed, polymer nanoparticles havebeen formulated with nanomolar affinity against target peptides andproteins using only combinations of hydrophobic and charged groups.These interactions mimic those arising from side chains of amino acids.However, nature also uses other functional groups includingoligosaccharides, glycosaminoglycans (GAGs), and theirpost-translationally modified derivatives including phosphorylated andsulfated carbohydrates and proteins to regulate biological function.Incorporation of these functional groups into a synthetic copolymer hasthe potential to improve affinity and/or broaden target scope. Thisbackground provides guidance for the present invention, the rationaldesign of an abiotic protein affinity reagents. It should be notedhowever, affinity alone may not be sufficient to influence function of aprotein associated with maintenance of homeostasis such as a signalingprotein, since inhibition of the protein's function requires masking thefunctional domain. A recent demonstration of this point comes fromMaynard et al (Christman, K. L. et al., J. Am. Chem. Soc. (2008)130:16585-16591; Nguyen, T. H. et al. Nat Chem (2013) 5:221-227).Although a poly(styrenesulfonate) polymer stabilizes basic fibroblastgrowth factor (bFGF) by covalent attachment, the polymer did not inhibitthe proteins activity (Christman, K. L. et al., J. Am. Chem. Soc. (2008)130:16585-16591; Nguyen, T. H. et al. Nat Chem (2013) 5:221-227).

Thus there is a need in the art for improved abiotic protein affinityreagents. The present invention satisfies this unmet need.

SUMMARY OF THE INVENTION

The present invention includes an abiotic, synthetic polymercomposition, comprising: N-isopropylacrylamide (NIPAm);N-tert-butylacrylamide (TBAm); N,N′-methylenebisacrylamide (Bis); and asulfated monomer.

In one embodiment, the composition has affinity to vascular endothelialgrowth factor (VEGF). In one embodiment, the sulfated monomer is amono-sulfated N-acetylglucosamine (GlcNAc). In one embodiment, theGlcNAc is selected from the group consisting of 3S-GlcNAc, 4S-GlcNAc,and 6S-GlcNAc. In one embodiment, the sulfated monomer is thetri-sulfated N-acetylglucosamine 3,4,6S-GlcNAc. In one embodiment, thecomposition comprises between 30% and 70% NIPAm. In one embodiment, thecomposition comprises between 30% and 50%. TBAm. In one embodiment, thecomposition comprises between 0% and 10% Bis. In one embodiment, thecomposition comprises between 1% and 20% GlcNAc. In one embodiment, thecomposition comprises between 1% and 20% 3,4,6S-GlcNAc. In oneembodiment, the composition comprises 56.3% NIPAm, 40% TBAm, 2% Bis, and1.7% 3,4,6S-GlcNAc.

In one embodiment, the composition is a nanoparticle. In one embodiment,the composition further comprises at least one therapeutic agent.

The present invention also includes a method of treating cancer in asubject, comprising administering to a subject a therapeuticallyeffective amount of an abiotic, synthetic polymer composition havingaffinity to VEGF.

In one embodiment, the composition comprises N-isopropylacrylamide(NIPAm), N-tert-butylacrylamide (TBAm), N,N′-methylenebisacrylamide(Bis), and a sulfated monomer. In one embodiment, the sulfated monomeris a mono-sulfated N-acetylglucosamine (GlcNAc). In one embodiment, theGlcNAc is selected from the group consisting of 3S-GlcNAc, 4S-GlcNAc,and 6S-GlcNAc. In one embodiment, the sulfated monomer is thetri-sulfated N-acetylglucosamine 3,4,6S-GlcNAc. In one embodiment, thecomposition comprises between 30% and 70% NIPAm. In one embodiment, thecomposition comprises between 30% and 50%. TBAm. In one embodiment, thecomposition comprises between 0% and 10% Bis. In one embodiment, thecomposition comprises between 1% and 20% GlcNAc. In one embodiment, thecomposition comprises between 1% and 20% 3,4,6S-GlcNAc. In oneembodiment, the composition comprises 56.3% NIPAm, 40% TBAm, 2% Bis, and1.7% 3,4,6S-GlcNAc. In one embodiment, the composition is ananoparticle. In one embodiment, the composition is administered with atherapeutic agent. In one embodiment, the therapeutic agent is theanti-tumor agent doxorubicin.

The present invention also includes a method of inhibiting angiogenesisin a subject, comprising administering to a subject a therapeuticallyeffective amount of an abiotic, synthetic polymer composition havingaffinity to VEGF.

In one embodiment, the composition comprises N-isopropylacrylamide(NIPAm), N-tert-butylacrylamide (TBAm), N,N′-methylenebisacrylamide(Bis), and a sulfated monomer. In one embodiment, the sulfated monomeris a mono-sulfated N-acetylglucosamine (GlcNAc). In one embodiment, theGlcNAc is selected from the group consisting of 3S-GlcNAc, 4S-GlcNAc,and 6S-GlcNAc. In one embodiment, the sulfated monomer is thetri-sulfated N-acetylglucosamine 3,4,6S-GlcNAc. In one embodiment, thecomposition comprises between 30% and 70% NIPAm. In one embodiment, thecomposition comprises between 30% and 50%. TBAm. In one embodiment, thecomposition comprises between 0% and 10% Bis. In one embodiment, thecomposition comprises between 1% and 20% GlcNAc. In one embodiment, thecomposition comprises between 1% and 20% 3,4,6S-GlcNAc. In oneembodiment, the composition comprises 56.3% NIPAm, 40% TBAm, 2% Bis, and1.7% 3,4,6S-GlcNAc. In one embodiment, the composition is ananoparticle. In one embodiment, the method is capable of treatingcancer. In one embodiment, the composition is administered with atherapeutic agent. In one embodiment, the therapeutic agent is theanti-tumor agent doxorubicin.

The present invention also includes a method of detecting cancer in asubject, comprising the steps of: acquiring a biological sample from thesubject; and quantifying the amount of VEGF present in the biologicalsample using an abiotic, synthetic polymer composition having affinityto VEGF.

In one embodiment, the composition comprises N-isopropylacrylamide(NIPAm), N-tert-butylacrylamide (TBAm), N,N′-methylenebisacrylamide(Bis), and a sulfated monomer. In one embodiment, the biological sampleis a fluid sample.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of exemplary embodiments of theinvention will be better understood when read in conjunction with theappended drawings. It should be understood, however, that the inventionis not limited to the precise arrangements and instrumentalities of theembodiments shown in the drawings.

FIG. 1A through FIG. 1D depict the functional (FIG. 1A) and sulfonateand sulfated (FIG. 1B) monomers used for nanoparticle synthesis and aschematic showing the general synthesis of polymer nanoparticles (NP)and their chemical composition. Nanoparticle numbering is correlatedwith the functional anionic monomer used. (FIG. 1C) TEM image of NP11.Bar: 1 μm. (FIG. 1D) High magnification TEM image of NP11. Bar: 100 nm.

FIG. 2A through FIG. 2E is a table depicting monomer composition, size,zeta-potential, and yield of the NPs. The monomer structures can befound in FIG. 1A and FIG. 1B. (FIG. 2A) AS, (FIG. 2B) 3S-GlcNAc, (FIG.2C) 4S-GlcNAc, (FIG. 2D) 6S-GlcNAc and (FIG. 2E) 3,4,6S-GlcNAc. N.D.;Not determined.

FIG. 3A through FIG. 3D are a series of graphs depicting therelationship between feed and incorporate percentage of sulfonatemonomer in NPs. FIG. 3A depicts 3,4,6S-GlcNAc; FIG. 3B depicts3S-GlcNAc; FIG. 3C depicts 4S-GlcNAc; FIG. 3D depicts 6S-GlcNAc).Incorporation percentage was calculated by 1HNMR.

FIG. 4A through FIG. 4D depict the results of screening polymernanoparticles interacting with VEGF₁₆₅. Quartz crystal microbalance(QCM) was used to analyze VEGF₁₆₅-NP interaction. The surface of the QCMwas functionalized with VEGF₁₆₅ and solutions of NPs were added to theQCM cells. (FIG. 4A) VEGF₁₆₅ affinity of NP1-NP4. (FIG. 4B) VEGF₁₆₅affinity of NP5, NP7 and NP9. (FIG. 4C) VEGF₁₆₅ affinity of NP6, NP8 andNP10. (FIG. 4D) VEGF₁₆₅ affinity of NP1, NP11, NP12 and NP13.

FIG. 5A and FIG. 5B depict the results of QCM analysis of NP-VEGF₁₆₅interaction. (FIG. 5A) Affinity of BSA to NP1, NP11-NP13. The surface ofthe QCM was functionalized with BSA and solutions of NPs were added tothe QCM cells. NP1 (Purple); NP11 (Red); NP12 (Blue); NP13 (Green).(FIG. 5B) Affinity of VEGF₁₆₅ to NP2. The surface of the QCM wasfunctionalized with VEGF₁₆₅ and solutions of NP11 or PBS was added tothe QCM cells. After washing with PBS, VEGF₁₆₅ was added into NP11immobilized QCM cell to demonstrate binding affinity of VEGF₁₆₅ to NP11.NP11 (Red); PBS (Black).

FIG. 6A depicts the monomer composition, size, -potential and yield ofthe NP11, NP14, and NP15.

FIG. 6B depicts the results of QCM analysis of VEGF₁₆₅-NP interaction.The surface of the QCM was functionalized with VEGF₁₆₅ and solutions ofNPs were added to the QCM cells.

FIG. 7 depicts the results of QCM analysis of VEGF 121-NP interaction.The surface of the QCM was functionalized with VEGF 121 and solutions ofNPs were added to the QCM cells.

FIG. 8A through FIG. 8D depict the results of in vitro VEGF-inhibitionexperiments and comparison with heparin. (FIG. 8A) Inhibition ofVEGF₁₆₅-dependent VEGFR-2 phosphorylation by NP11. (FIG. 8B) Inhibitionof VEGF₁₆₅-dependent cell growth by NP1, NP11-NP13. Significantdifferences: *p<0.05 and ***p<0.001 vs. 0 μg/mL. (FIG. 8C) Factor Xa(FXa) binding study to AT III. After incubation of AT III with severalconcentration of NP11, UFH or LMWH (Dalteparin), FXa was added. Then,the remaining FXa was measured. (FIG. 8D) Inhibition ofVEGF₁₆₅-dependent cell growth heparin (UFH or LMWH (dalteparin))Significant differences: *p<0.05 and ***p<0.001 vs. 0 μg/mL.

FIG. 9A through FIG. 9C depict the results of experiments demonstratinginhibition of VEGF₁₆₅-dependent VEGFR-2 phosphorylation by NP1, NP12, orNP13. Human umbilical vein endothelial cells (HUVECs) were incubatedwith EBM-2 containing 20 ng/mL of VEGF₁₆₅ and different concentration ofNPs for 2 h at 37° C. The cells were then lysed. The VEGFR andphosphorylated VEGFR (Tyr951) were evaluated by Western blotting.

FIG. 10 depicts the results of experiments investigating the uptake ofNP11 into HUVEC. HUVECs were incubated with FITC-labeled NP11 for 24 hat 37° C. The cells were then lysed and fluorescence was measured.

FIG. 11 depicts the results of a cytotoxicity assay of NPs using HUVECs.HUVECs were treated with EGM-2 and various concentrations of NPs.Forty-eight hours after addition, viable cells were determined by MTTassay.

FIG. 12A through FIG. 12D depict the anti-angiogenic effects of NPs.(FIG. 12A) Inhibition of VEGF₁₆₅-dependent cell motility by NP1,NP11-NP13. Bar: 30 μm. (FIG. 12B) Inhibition of VEGF₁₆₅-dependencapillary tube formation in the presence of NP1, NP11-NP13. Bar: 30 μm.(FIG. 12C) Inhibition of in vivo angiogenesis in Matrigel plugsimplanted in mice. Plugs were removed from mice and photographed after10 days. (FIG. 12D) Hemoglobin (Hb) content within Matrigel plugs wasquantified and depicted as the percent of Hb. Significant differences:***p<0.001 vs. Control (+)

FIG. 13A through FIG. 13C depict the results of experimentsdemonstrating the inhibition of VEGF₁₆₅-dependent cell motility (FIG.13A) and invasion (FIG. 13B, FIG. 13C) by NPs. The number of cells thathad invaded through the insert was counted under a fluorescencemicroscope. Significant differences: ***p<0.001 vs. Control (+) Bar: 30μm.

FIG. 14 depicts the results of experiments demonstrating the inhibitionof VEGF₁₆₅-dependent capillary tube formation in the presence of NPs.The length of tubes was calculated by using the software Image J.Significant differences: ***p<0.001 vs. only VEGF.

FIG. 15A through FIG. 15D depict schematic images of the interaction ofheparins and VEGF₁₆₅ with NPs of various compositions. (FIG. 15A)Heparin and VEGF₁₆₅ interaction. (FIG. 15B) VEGF₁₆₅ interaction with NPsthat lack TBAm, a hydrophobic monomer (NP15). (FIG. 15C) VEGF₁₆₅interaction with NPs containing TBAm and 5% Mono-sulfated GlcNAc monomer(NP10). (FIG. 15D) VEGF₁₆₅ interaction with NPs containing TBAm and 1.7%3,4,6 tri-sulfated monomer containing (NP11).

FIG. 16A through 16G depict the results of experiments demonstratingtumor growth inhibition by combination therapy of NPs and Dox. (FIG.16A) Biodistribution of 14C labeled NP11 in tumor-bearing mice at 30 minor 1 hour after the intravenous injection of NP11. (FIG. 16B)Biodistribution of 14C labeled NP11 in normal mice at 2 or 4 weeks afterthe intravenous injection of NP11. (FIG. 16C through FIG. 16E)Therapeutic effect of NP11 using tumor-bearing mice. (FIG. 16C) The micewere intravenously injected with PBS or NP11 (5, 10, 20 or 40 mg/kg) at5, 7, 9, and 11 days after tumor implantation. Significant difference:*p<0.05; Control vs 10 or 20 mg/kg, **p<0.01; Control vs 40 mg/kg. (FIG.16D, FIG. 16E) The mice were intravenously injected with NP11 (20 or 40mg/kg,) at day 5, 7, 9 and 11 days, and doxorubicin ((FIG. 16D) 2.5 or(FIG. 16E) 5 mg/kg) at day 6, 8, 10 and 12 days after the tumorinoculation. Black arrows show NPs injection day. Red arrows show Doxinjection day. Significant differences: ***p<0.01; vs PBS, # p<0.05; vsDox and ## p<0.01; vs Dox. (FIG. 16F) Blood perfusion efficiency. Lectinperfusion and CD31 staining of Colon tumor sections. Green colorindicates CD31 positive cells, red color indicates lectin positive cellsand yellow color indicates double-stained vessel area. White bar shows50 μm. (FIG. 16G) Dox concentration in tumor after the final Doxinjection. Significant difference: *p<0.05; Dox alone vs NP11 and Dox.

DETAILED DESCRIPTION

The present invention relates to compositions and methods comprisingabiotic, synthetic polymers with affinity and specificity to proteins.The synthetic polymers are an improvement over biological agents byproviding a simpler, less expensive, and customizable platform forbinding to proteins. In one embodiment, the compositions and methodsrelate to synthetic polymers with affinity and specificity to vascularendothelial growth factor (VEGF).

In one embodiment, the compositions are useful for treating diseases anddisorders related to the overexpression of VEGF. In one embodiment, thecompositions are useful for treating cancer. In one embodiment, thecompositions are useful for detecting VEGF levels from biologicalsamples. In one embodiment, the compositions are useful for detectingoverexpression of VEGF from biological samples. In one embodiment, thecompositions are used to diagnose cancer.

Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, exemplary methods andmaterials are described.

As used herein, each of the following terms has the meaning associatedwith it in this section.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

“About” as used herein when referring to a measurable value such as anamount, a temporal duration, and the like, is meant to encompassvariations of ±20% or ±10%, more preferably ±5%, even more preferably±1%, and still more preferably ±0.1% from the specified value, as suchvariations are appropriate to perform the disclosed methods.

The term “abnormal” when used in the context of organisms, tissues,cells, or components thereof refers to those organisms, tissues, cells,or components thereof that differ in at least one observable ordetectable characteristic (e.g., age, treatment, time of day, etc.) fromthose organisms, tissues, cells, or components thereof that display the“normal” (expected/homeostatic) respective characteristic.Characteristics which are normal or expected for one cell, tissue type,or subject might be abnormal for a different cell or tissue type.

As used herein, a “disease” is a state of health of an individualwherein the individual cannot maintain homeostasis, and wherein if thedisease is not ameliorated then the individual's health continues todeteriorate.

As used herein, a “disorder” in an individual is a state of health inwhich the individual is able to maintain homeostasis, but in which theindividual's state of health is less favorable than it would be in theabsence of the disorder. Left untreated, a disorder does not necessarilycause a further decrease in the individual's state of health.

As used herein, the term “treating” means ameliorating the effects of,or reducing, delaying, halting, reversing, diminishing, or eliminatingthe frequency or the occurrence or the severity of at least one sign orsymptom of a disease or disorder.

As used herein, the terms “effective amount” or “therapeuticallyeffective amount” or “pharmaceutically effective amount” of acomposition are used interchangeably to refer to the amount of thecomposition that is sufficient to provide a beneficial effect to thesubject to which the composition is administered. An appropriatetherapeutic amount in any individual case may be determined by one ofordinary skill in the art using routine experimentation.

As used herein, a “therapeutic” treatment is a treatment administered toan individual who exhibits signs or symptoms of a disease or disorderfor the purpose of ameliorating the effects of, or reducing, delaying,halting, reversing, diminishing, or eliminating the frequency oroccurrence or the severity of at least one of those signs or symptoms.

As used herein, the term “pharmaceutically acceptable” refers to amaterial, such as a carrier or diluent, that does not abrogate thebiological activity or properties of a compound and is relativelynon-toxic; i.e., the material may be administered to an individualwithout causing undesirable biological effects or interacting in adeleterious manner with any of the components of a composition in whichit is contained.

As used herein, a “pharmaceutically acceptable carrier” means apharmaceutically acceptable material, composition, or carrier, such as aliquid or solid filler, diluent, excipient, solvent, or encapsulatingmaterial, involved in carrying or transporting at least one compound ofthe present invention within or to the subject such that it can performits intended function. Each carrier must be “acceptable” in the sense ofbeing compatible with the other ingredients of the formulation, and notbe injurious to the patient. Some examples of materials that can serveas pharmaceutically acceptable carriers include: sugars, such aslactose, glucose, and sucrose; starches, such as corn starch and potatostarch; cellulose and its derivatives, such as sodium carboxymethylcellulose, ethyl cellulose, and cellulose acetate; powdered tragacanth;malt; gelatin; talc; excipients, such as cocoa butter and suppositorywaxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesameoil, olive oil, corn oil, and soybean oil; glycols, such as propyleneglycol; polyols, such as glycerin, sorbitol, mannitol, and polyethyleneglycol; esters, such as ethyl oleate and ethyl laurate; agar; bufferingagents, such as magnesium hydroxide and aluminum hydroxide; alginicacid; pyrogen-free water; isotonic saline; Ringer's solution; ethylalcohol; phosphate buffer solutions; and other non-toxic compatiblesubstances employed in pharmaceutical formulations. As used herein,“pharmaceutically acceptable carrier” also includes any and allcoatings, antibacterial and antifungal agents, absorption delayingagents, and the like that are compatible with the activity of a compoundand are physiologically acceptable to a subject. Supplementary activecompounds can also be incorporated into the compositions.

As used herein, the term “polymer” refers to a molecule composed ofrepeating structural units typically connected by covalent chemicalbonds. The term “polymer” is also meant to include the terms copolymerand oligomers. In one embodiment, a polymer comprises a backbone (i.e.,the chemical connectivity that defines the central chain of the polymer,including chemical linkages among the various polymerized monomericunits) and a side chain (i.e., the chemical connectivity that extendsaway from the backbone).

As used herein, the terms “subject” or “individual” or “patient” refersto a human or other mammal (e.g., primate, dog, cat, goat, horse, pig,mouse, rat, rabbit, and the like) that can have a vascular endothelialgrowth factor (VEGF) overexpression-related condition or be at risk fordeveloping a VEGF overexpression-related condition, but may or may nothave a VEGF overexpression-related condition or be at risk fordeveloping a VEGF overexpression-related condition.

Ranges: throughout this disclosure, various aspects of the invention canbe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, and 6. Thisapplies regardless of the breadth of the range.

Compositions

The present invention provides compositions comprising abiotic,synthetic polymers with affinity and specificity to proteins and methodsof use thereof. In certain embodiments, the invention comprisessynthetic polymers with affinity and specificity to vascular endothelialgrowth factor (VEGF). In certain embodiments, the invention is used todetect and/or treat diseases related to VEGF overexpression.

The present invention is partly based upon the discovery that syntheticpolymers comprising N-isopropylacrylamide (NIPAm),N-tert-butylacrylamide (TBAm), sulfonated and sulfated monomers, and N,N′-methylenebisacrylamide (Bis) having binding affinity to VEGF. Thus,the synthetic polymers are able to bind to VEGF and inhibit downstreamevents such as angiogenesis and cancer.

In some embodiments, the sulfonated monomer is2-acrylamido-2-methylpropane sulfonic acid (AS). In some embodiments,the sulfated monomer is an N-acetylglucosamine (GlcNAc). In variousembodiments, the sulfated monomer is an isomer of GlcNAc, including butnot limited to 3S-GlcNAc, 4S-GlcNAc, or 6S-GlcNAc. In one embodiment,the sulfated monomer is 3,4,6S-GlcNAc.

In certain embodiments, the synthetic polymer may be described by theratio of its components. For example, in certain embodiments, thesynthetic polymers may comprise between 0 and 10% Bis. In certainembodiments, the synthetic polymers may comprise between 30 and 50%TBAm. In certain embodiments, the synthetic polymers may comprisebetween 30 and 70% NIPAm. In certain embodiments, the synthetic polymersmay comprise between 1 and 20% AS. In certain embodiments, the syntheticpolymers may comprise between 1 and 20% 3 S-GlcNAc. In certainembodiments, the synthetic polymers may comprise between 1 and 20%4S-GlcNAc. In certain embodiments, the synthetic polymers may comprisebetween 1 and 20% 6S-GlcNAc. In certain embodiments, the syntheticpolymers may comprise between 1 and 20% 3,4,6S-GlcNAc. In oneembodiment, the synthetic polymers comprise 56.3% NIPAm, 40% TBAm, 2%Bis, and 1.7% 3,4,6S-GlcNAc.

The synthetic polymers described herein may be prepared in any suitablemanner. Suitable synthetic methods used to produce the syntheticpolymers include, by way of non-limiting example, cationic, anionic, andfree radical polymerization. In some instances, when a cationic processis used, the monomer is treated with a catalyst to initiate thepolymerization. Optionally, one or more monomers may be used to form acopolymer. In some embodiments, a catalyst is used an initiator,including, e.g., protonic acids (Bronsted acid) or Lewis acids; in thecase of using Lewis acids some promoter such as water or alcohols arealso optionally used. In some embodiments, the catalyst is, by way ofnon-limiting example, hydrogen iodide, perchloric acid, sulfuric acid,phosphoric acid, hydrogen fluoride, chlorosulfonic acid, methansulfonicacid, trifluoromehtanesulfonic acid, aluminum trichloride, alkylaluminum chlorides, boron trifluoride complexes, tin tetrachloride,antimony pentachloride, zinc chloride, titanium tetrachloride,phosphorous pentachloride, phosphorus oxychloride, or chromiumoxychloride. In certain embodiments, polymer synthesis is performed neator in any suitable solvent. Suitable solvents include, but are notlimited to, pentane, hexane, dichloromethane, chloroform, or dimethylformamide (DMF). In certain embodiments, the polymer synthesis isperformed at any suitable reaction temperature, including, e.g., fromabout −50° C. to about 100° C., or from about 0° C. to about 70° C.

In certain embodiments, the synthetic polymers are prepared by freeradical polymerization. When a free radical polymerization process isused, the monomer, optionally, the co-monomer, and an optional source offree radicals are provided to trigger the free radical polymerizationprocess. In some embodiments, the source of free radicals are optionalbecause some monomers may self-initiate upon heating at hightemperature. In certain instances, after forming the polymerizationmixture, the mixture is subjected to polymerization conditions.Polymerization conditions are those conditions that cause at least onemonomer to form at least one polymer, as discussed herein. Suchconditions are optionally varied to any suitable level and include, byway of non-limiting example, temperature, pressure, atmosphere, ratiosof starting components used in the polymerization mixture, and reactiontime. The polymerization is carried out in any suitable manner,including, e.g., in solution, dispersion, suspension, emulsion, or bulk.

Polymerization processes described herein optionally occur in anysuitable solvent or mixture thereof. Suitable solvents include water,alcohol (e.g., methanol, ethanol, n-propanol, isopropanol, butanol),tetrahydrofuran (THF) dimethyl sulfoxide (DMSO), dimethylformamide(DMF), acetone, acetonitrile, hexamethylphosphoramide, acetic acid,formic acid, hexane, cyclohexane, benzene, toluene, dioxane, methylenechloride, ether (e.g., diethyl ether), chloroform, and ethyl acetate. Inone aspect, the solvent includes water, and mixtures of water andwater-miscible organic solvents such as DMF.

Particle Size

In certain embodiments, the abiotic, synthetic polymers of the presentinvention are assembled into nanoparticles (NP). The NP provided hereincan have any suitable size. NP sizes may be adjusted to meet specificneeds by adjusting the proportion of components contained therein. Inspecific embodiments, the NP provided herein have an averagehydrodynamic diameter of about 10 nm to about 200 nm. In more specificembodiments, the NP provided herein have an average hydrodynamicdiameter of about 1 nm to about 500 nm, about 5 nm to about 250 nm,about 10 nm to about 200 nm, about 10 nm to about 100 nm, about 20 nm toabout 100 nm, about 30 nm to about 90 nm, and the like. Particle sizecan be determined in any suitable manner, including, but not limited to,by gel permeation chromatography (GPC), dynamic light scattering (DLS),electron microscopy techniques (e.g., TEM), and other methods.

Therapeutic Agents

Provided in certain embodiments herein is a NP comprising the abiotic,synthetic polymers of the present invention and at least one therapeuticagent. The NP is capable of binding to VEGF and localizing in regions ofincreased VEGF expression and accumulation, and is thereby capable ofproviding sustained drug delivery of the at least one therapeutic agent.Thus, the NP can provide targeted drug delivery to regions of increasedVEGF expression and accumulation. In one embodiment, the at least onetherapeutic agent comprises an anti-tumor agent. The therapeutic agentcan include any naturally occurring, synthetic, inorganic, organic,peptide, enzyme, nucleic acid small molecule, and the like, which has atleast some activity in treating and/or preventing cancer.

Typical anti-tumor agents include, but are not limited to, pyrimidineantimetabolites such as 5-fluorouracil (5FU), tegafur, carmofur,doxifluridine, broxuridine, cytarabine, enocitabine, hydroxypyridine,hydroxycarbamide, methotrexate, fludarabine phosphate and the like;purine antimetabolites such as 6-mercaptopurine, 6-thioguanine,thioinosine, gemcitabine hydrochloride etc., and the like; cisplatin,carboplatin, nedaplatin, oxaliplatin and the like; nitrogen mustardalkylating agents such as nitrogen mustard, nitrogen mustard N-oxide,chlorambucil and the like; ethylenimine derivatives such as carboquone,thiotepa and the like; sulfonates such as busulfan, improsulfan tosylateand the like; nitrosourea derivatives such as nimustine hydrochlorideetc., and the like; mitomycin C, bleomycin, peplomycin, daunorubicin,aclarubicin, doxorubicin, pirarubicin, THP-adriamycin,4′-epidoxorubicin, epirubicin and the like; chromomycin A3, actinomycinD and the like; vinca alkaloids such as vinblastine, vincristine,vindesine and the like; epipodophyllotoxins such as etoposide,teniposide and the like; taxane alkaloids such as paclitaxel, docetaxeletc., and the like; molecule target therapeutic agents includingimatinib, gefitinib, erlotinib, vandetanib, sunitinib, sorafenib,rituximab, cetuximab, infliximab, trastuzumab, bevacizumab, and thelike,

In other embodiments, the present invention is not limited to anyparticular therapeutic agent, but rather encompasses any suitabletherapeutic agent that can be embedded within a NP. Exemplarytherapeutic agents include, but are not limited to, anti-viral agents,anti-bacterial agents, chemotherapeutic agents, anti-inflammatoryagents, antiseptics, anesthetics, analgesics, pharmaceutical agents,small molecules, peptides, nucleic acids, and the like.

In certain embodiments, the NP described herein comprise at least oneantibacterial agent. In one embodiment, the antibacterial agent is abroad-spectrum antibacterial agent. Suitable antibacterial agentsinclude, but are not limited to, chlorhexidine and derivatives thereof,members of the bisbiguanide class of inhibitors, povidone iodine,hydrogen peroxide, doxycycline, minocycline, clindamycin, doxycycline,metronidazole, essential oil extracts (menthol, thymol, eucalyptol,methyl salicylate, metal salts (zinc, copper, stannous ions), phenols(triclosan), all quaternary ammonium compounds (cetylpyridiniumchloride), surfactants (sodium lauryl sulphate, delmopinol), all naturalmolecules (phenols, phenolic acids, quinones, alkaloids, lectins,peptides, polypeptides, indole derivatives, flustramine derivatives,carolacton, halogenated furanones, oroidin analogues, agelasine,ageloxime D).

In various embodiments, the at least one therapeutic agent is attachedto the NP in any suitable manner. For example, attachment may beachieved through covalent bonds, non-covalent interactions, staticinteractions, hydrophobic interactions, or combinations thereof.

In some embodiments, therapeutic agents are selected from, by way ofnon-limiting example, at least one nucleotide (e.g., a polynucleotide),at least one carbohydrate or at least one amino acid (e.g., a peptide).In specific embodiments, the therapeutic agent is a polynucleotide, anoligonucleotide, a gene expression modulator, a knockdown agent, ansiRNA, an RNAi agent, a dicer substrate, an miRNA, an shRNA, anantisense oligonucleotide, or an aptamer. In other embodiments, thetherapeutic agent is an aiRNA (Asymmetric RNA duplexes mediate RNAinterference in mammalian cells. Xiangao Sun, Harry A Rogoff, Chiang JLi Nature Biotechnology 26, 1379-1382 (2008)). In certain embodiments,the therapeutic agent is a protein, peptide, dominant-negative protein,enzyme, antibody, or antibody fragment. In some embodiments, thetherapeutic agent is a carbohydrate, or a small molecule. In someembodiments, the therapeutic agent is an abiotic, synthetic polymer.

In some embodiments, a therapeutic agent is chemically conjugated to theNP and/or to one or more polymer of the NP by any suitable chemicalconjugation technique. Therapeutic agents are optionally conjugated toan end of the polymer, or to a pendant side chain of the polymer. Insome embodiments, NP containing a therapeutic agent are formed byconjugation of the agent with a polymer and subsequently forming the NPin any suitable manner, e.g., by self-assembly of the resultingconjugates into a NP comprising the agent. The covalent bond between apolymer and a therapeutic agent of a NP described herein is, optionally,non-cleavable, or cleavable. In some embodiments, conjugation is alsoperformed with pH-sensitive bonds and linkers, including, but notlimited to, hydrazone and acetal linkages.

In certain embodiments, the NP of the invention comprise atherapeutically effective amount of at least one therapeutic agent. Forexample, in one embodiment, the core of the NP is loaded with atherapeutically effective amount of at least one therapeutic agent. Therelative amount or concentration of the therapeutic agent may bedependent upon the size of the NP, type of therapeutic agent, conditionto be treated or prevented, and the like. In one embodiment, thetherapeutic agent is present at greater than about 0 wt %, or greaterthan about 5 wt %, or greater than about 10 wt %, or greater than about15 wt %, or greater than about 20 wt %, or greater than about 30 wt %,or greater than about 50 wt %, or greater than about 75 wt %. Forexample, it is demonstrated herein that the NP of the invention mayloaded with an amount or concentration of a therapeutic agent that ismuch greater than its minimum effective concentration. Thus, thecomposition of the invention is able to retain therapeutically effectiveamounts of a therapeutic agent within the NP.

In certain embodiments, the composition comprises a plurality ofdifferent NPs, each carrying a different therapeutic agent, therebyproviding combination therapy. For example, in one embodiment, thecomposition comprises a first NP, comprising an anti-tumor agent, and asecond NP, comprising a chemotherapeutic agent. In another embodiment,the composition comprises a first NP, comprising an anti-tumor agent, asecond NP, comprising a chemotherapeutic agent, and a third NP,comprising an anti-inflammatory agent. Each therapeutic agent hasdifferent yet complementary mechanisms of action, all aimed at treatingthe pathology. In one embodiment, the different NPs are mixed indifferent proportions to achieve maximum therapeutic effect. In oneembodiment, each of the different NPs can be configured for differentdrug delivery characteristics, thereby allowing different therapeuticagents to be delivered at different times, as necessitated by theparticular disorder or treatment.

Pharmaceutical Compositions and Formulations

The invention also encompasses the use of pharmaceutical compositions ofthe invention to practice the methods of the invention. Such apharmaceutical composition may consist of at least one compound, agent,NP, or NP conjugate of the invention in a form suitable foradministration to a subject, or the pharmaceutical composition maycomprise at least one compound, agent, NP, or NP conjugate of theinvention, and one or more pharmaceutically acceptable carriers, one ormore additional ingredients, or some combination of these.

In an embodiment, the pharmaceutical compositions useful for practicingthe methods of the invention may be administered to deliver a dose ofbetween 1 ng/kg/day and 100 mg/kg/day. In another embodiment, thepharmaceutical compositions useful for practicing the invention may beadministered to deliver a dose of between 1 ng/kg/day and 500 mg/kg/day.

The relative amounts of the active ingredient, the pharmaceuticallyacceptable carrier, and any additional ingredients in a pharmaceuticalcomposition of the invention will vary, depending upon the identity,size, and condition of the subject treated and further depending uponthe route by which the composition is to be administered. By way ofexample, the composition may comprise between 0.1% and 100% (w/w) activeingredient.

Pharmaceutical compositions that are useful in the methods of theinvention may be suitably developed for oral, rectal, vaginal,parenteral, topical, pulmonary, intranasal, buccal, ophthalmic, oranother route of administration. A composition useful within the methodsof the invention may be directly administered to the skin or any othertissue of a mammal. The route(s) of administration will be readilyapparent to the skilled artisan and will depend upon any number offactors including the type and severity of the disease being treated,the type and age of the subject being treated, and the like.

The formulations of the pharmaceutical compositions described herein maybe prepared by any method known or hereafter developed in the art ofpharmacology. In general, such preparatory methods include the step ofbringing the active ingredient into association with a carrier or one ormore other accessory ingredients, and then, if necessary or desirable,shaping or packaging the product into a desired single- or multi-doseunit.

As used herein, a “unit dose” is a discrete amount of the pharmaceuticalcomposition comprising a predetermined amount of the active ingredient.The amount of the active ingredient is generally equal to the dosage ofthe active ingredient that would be administered to a subject or aconvenient fraction of such a dosage such as, for example, one-half orone-third of such a dosage. The unit dosage form may be for a singledaily dose or one of multiple daily doses (e.g., about 1 to 4 or moretimes per day). When multiple daily doses are used, the unit dosage formmay be the same or different for each dose.

Although the descriptions of pharmaceutical compositions provided hereinare principally directed to pharmaceutical compositions that aresuitable for ethical administration to humans, it will be understood bythe skilled artisan that such compositions are generally suitable foradministration to animals of all sorts. Modification of pharmaceuticalcompositions suitable for administration to humans in order to renderthe compositions suitable for administration to various animals is wellunderstood, and the ordinarily skilled veterinary pharmacologist maydesign and perform such modification with merely ordinary, if any,experimentation. Subjects to which administration of the pharmaceuticalcompositions of the invention is contemplated include, but are notlimited to, humans and other primates, mammals including commerciallyrelevant mammals such as cattle, pigs, horses, sheep, cats, and dogs.

In one embodiment, the compositions of the invention are formulatedusing one or more pharmaceutically acceptable excipients or carriers. Inone embodiment, the pharmaceutical compositions of the inventioncomprise a therapeutically effective amount of a compound, agent, NP, orNP conjugate of the invention and a pharmaceutically acceptable carrier.Pharmaceutically acceptable carriers that are useful, include, but arenot limited to, glycerol, water, saline, ethanol and otherpharmaceutically acceptable salt solutions such as phosphates and saltsof organic acids.

The carrier may be a solvent or dispersion medium containing, forexample, water, ethanol, polyol (for example, glycerol, propyleneglycol, and liquid polyethylene glycol, and the like), suitable mixturesthereof, and vegetable oils. The proper fluidity may be maintained, forexample, by the use of a coating such as lecithin, by the maintenance ofthe required particle size in the case of dispersion and by the use ofsurfactants. Prevention of the action of microorganisms may be achievedby various antibacterial and antifungal agents, for example, parabens,chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In manycases, the carrier may include isotonic agents, for example, sugars,sodium chloride, or polyalcohols such as mannitol and sorbitol, in thecomposition. Prolonged absorption of the injectable compositions may bebrought about by including in the composition an agent that delaysabsorption, for example, aluminum monostearate or gelatin.

Formulations may be employed in admixtures with conventional excipients,i.e., pharmaceutically acceptable organic or inorganic carriersubstances suitable for oral, vaginal, parenteral, nasal, intravenous,subcutaneous, enteral, or any other suitable mode of administration,known to the art. The pharmaceutical preparations may be sterilized andif desired mixed with auxiliary agents, e.g., lubricants, preservatives,stabilizers, wetting agents, emulsifiers, salts for influencing osmoticpressure buffers, coloring, flavoring and/or aromatic substances and thelike. They may also be combined where desired with other active agents,e.g., other analgesic agents.

As used herein, “additional ingredients” include, but are not limitedto, one or more of the following: excipients; surface active agents;dispersing agents; inert diluents; granulating and disintegratingagents; binding agents; lubricating agents; sweetening agents; flavoringagents; coloring agents; preservatives; physiologically degradablecompositions such as gelatin; aqueous vehicles and solvents; oilyvehicles and solvents; suspending agents; dispersing or wetting agents;emulsifying agents, demulcents; buffers; salts; thickening agents;fillers; emulsifying agents; antioxidants; antibiotics; antifungalagents; stabilizing agents; and pharmaceutically acceptable polymeric orhydrophobic materials.

The composition of the invention may comprise a preservative from about0.005% to 2.0% by total weight of the composition. The preservative isused to prevent spoilage in the case of exposure to contaminants in theenvironment. Examples of preservatives useful in accordance with theinvention included but are not limited to those selected from the groupconsisting of benzyl alcohol, sorbic acid, parabens, imidurea andcombinations thereof. In one embodiment, the preservative is acombination of about 0.5% to 2.0% benzyl alcohol and 0.05% to 0.5%sorbic acid.

In certain embodiments, the composition includes an anti-oxidant and achelating agent that inhibits degradation. Antioxidants include BHT,BHA, alpha-tocopherol, and ascorbic acid in the ranges of about 0.01% to0.3% and BHT in the range of 0.03% to 0.1% of the total weight of thecomposition. The chelating agent may be present in an amount of from0.01% to 0.5% of the total weight of the composition. Chelating agentsinclude edetate salts (e.g. disodium edetate) and citric acid in theweight range of about 0.01% to 0.20% and in the range of 0.02% to 0.10%of the total weight of the composition. The chelating agent is usefulfor chelating metal ions in the composition that may be detrimental tothe shelf life of the formulation. Other suitable and equivalentantioxidants and chelating agents may be substituted therefore as wouldbe known to those skilled in the art.

Detection Platforms

The present invention provides platforms for detecting VEGF usingsynthetic polymers. The synthetic polymers disclosed herein may be usedin a manner similar to antibodies for capturing, labeling, detecting,and quantifying VEGF. The detection platforms are therefore useful fordiagnosing diseases and conditions related to VEGF expression.

In various embodiments, the synthetic polymers of the present inventionmay be used in any protein detection platform commonly used in the art.Suitable detection platforms include but are not limited to colorimetricsystems, chemiluminescence systems, bioluminescence systems,chemifluorescence systems, autoradiography systems, and immunogoldlabeling. In any of the suitable detection platforms, the VEGF-specificantibodies may be replaced or supplemented with the synthetic polymersof the present invention for more efficient and cost-effective means ofVEGF capturing and/or labeling.

Examples of an assay or methodology where the synthetic polymers of thepresent invention may be used include, but are not limited to, animmunochromatography assay, an immunodot assay, a Luminex assay, anELISA assay, an ELISPOT assay, a protein microarray assay, aligand-receptor binding assay, an immunostaining assay, a Western blotassay, a mass spectrophotometry assay, a radioimmunoassay (MA), aradioimmunodiffusion assay, a liquid chromatography-tandem massspectrometry assay, an ouchterlony immunodiffusion assay, reverse phaseprotein microarray, a rocket immunoelectrophoresis assay, animmunohistostaining assay, an immunoprecipitation assay, a complementfixation assay, FACS, an enzymatic assay, an enzymatic assay employing adetectable molecule, such as a chromophore, fluorophore, or radioactivesubstrate, a substrate binding assay employing such a substrate, and aprotein chip assay.

In certain embodiments, the synthetic polymers of the present inventionmay be used in a biosensor detection platform. Biosensors typicallyinclude a transducer that generates a measurable signal in response to abinding event with a target analyte. The transducers can be any suitabletransducer platform, including but not limited to nanosheets,nanoparticles, nanowires, and the like constructed from materials suchas graphene, silicon, silver, and the like. By way of non-limitingexample, the synthetic polymers of the present invention may beincorporated into the biosensor detection platform by deposition,growth, or grafting onto the transducer platform, or alternatively thetransducer platform may be coated with NP comprising the syntheticpolymer.

Methods of Use

The present invention provides a method of treating diseases anddisorders related to the overexpression of a target molecule. Thepresent invention also provides a method of detecting the level of atarget molecule from biological samples and diagnosing diseases anddisorders related to the overexpression of a target molecule.

In some embodiments, the target molecule is VEGF. Thus, the presentinvention provides a method of treating diseases and disorders relatedto the overexpression of VEGF. The present invention also provides amethod of detecting VEGF levels from biological samples and diagnosingdiseases and disorders related to the overexpression of VEGF.

As described herein, the synthetic polymers described herein having anaffinity and specificity for VEGF, wherein binding of the syntheticpolymers to VEGF inhibits downstream events such as angiogenesis. Assuch, the compositions comprising the synthetic polymers describedherein are useful as anti-angiogenesis agents to halt tumor growth. Inother embodiments, the affinity of the synthetic polymers to VEGF allowsthe synthetic polymers to act as a homing composition to providesustained and localized delivery of therapeutic agents to target sitesof VEGF overexpression, such as cancerous tissue.

The method of the invention can be used to treat any type of cancer.Non-limiting examples include B cell lymphoma, T cell lymphoma, myeloma,leukemia, hematopoietic neoplasias, thymoma, lymphoma, sarcoma, lungcancer, non-Hodgkins lymphoma, Hodgkins lymphoma, uterine cancer,adenocarcinoma, breast cancer, pancreatic cancer, lung cancer, renalcancer, bladder cancer, prostate cancer, ovarian cancer, primary ormetastatic melanoma, squamous cell carcinoma, basal cell carcimona,hepatocellular carcinoma, brain cancer, angiosarcoma, hemangiosarcoma,head and neck carcinoma, thyroid carcinoma, soft tissue sarcoma, bonesarcoma, testicular cancer, uterine cancer, cervical cancer,gastrointestinal cancer, and the like.

The treatment methods can be in any suitable form, including oraladministration, parenteral administration, topical administration, andthe like.

Parenteral Administration

As used herein, “parenteral administration” of a composition includesany route of administration characterized by physical breaching of atissue of a subject and administration of the pharmaceutical compositionthrough the breach in the tissue. Parenteral administration thusincludes, but is not limited to, administration of a pharmaceuticalcomposition by injection of the composition, by application of thecomposition through a surgical incision, by application of thecomposition through a tissue-penetrating non-surgical wound, and thelike. In particular, parenteral administration is contemplated toinclude, but is not limited to, subcutaneous, intraperitoneal,intramuscular, intrasternal injection, and kidney dialytic infusiontechniques.

Formulations of a pharmaceutical composition suitable for parenteraladministration comprise the active ingredient combined with apharmaceutically acceptable carrier, such as sterile water or sterileisotonic saline. Such formulations may be prepared, packaged, or sold ina form suitable for bolus administration or for continuousadministration. Injectable formulations may be prepared, packaged, orsold in unit dosage form, such as in ampules or in multi-dose containerscontaining a preservative. Formulations for parenteral administrationinclude, but are not limited to, suspensions, solutions, emulsions inoily or aqueous vehicles, pastes, and implantable sustained-release orbiodegradable formulations. Such formulations may further comprise oneor more additional ingredients including, but not limited to,suspending, stabilizing, or dispersing agents. In one embodiment of aformulation for parenteral administration, the active ingredient isprovided in dry (i.e., powder or granular) form for reconstitution witha suitable vehicle (e.g., sterile pyrogen-free water) prior toparenteral administration of the reconstituted composition.

The pharmaceutical compositions may be prepared, packaged, or sold inthe form of a sterile injectable aqueous or oily suspension or solution.This suspension or solution may be formulated according to the knownart, and may comprise, in addition to the active ingredient, additionalingredients such as the dispersing agents, wetting agents, or suspendingagents described herein. Such sterile injectable formulations may beprepared using a non-toxic parenterally-acceptable diluent or solvent,such as water. Other acceptable diluents and solvents include, but arenot limited to, Ringer's solution, isotonic sodium chloride solution,and fixed oils such as synthetic mono- or di-glycerides. Otherparentally-administrable formulations that are useful include those thatcomprise the active ingredient in microcrystalline form, in a liposomalpreparation, or as a component of a biodegradable polymer system.

Methods of Detection

The present invention also relates to a method of detecting a disease ordisorder of a subject by assessing the level of VEGF in a biologicalsample of the subject using the synthetic polymers of the presentinvention. In another embodiment, the invention is a method of assessingthe severity of a disease or disorder of a subject by assessing thelevel of VEGF in a biological sample of the subject using the syntheticpolymers of the present invention. In another embodiment, the inventionis a method of monitoring the effect of a treatment of a disease ordisorder of a subject by assessing the level of VEGF in a biologicalsample of the subject using the synthetic polymers of the presentinvention. In one embodiment, the biological sample of the subject is acell, tissue, or bodily fluid. Non-limiting examples of bodily fluids inwhich the level of VEGF can be assessed include, but are not limited to,blood, serum, plasma and urine. In various embodiments, the level ofVEGF in the biological sample of the subject is compared with the VEGFlevel in a comparator. Non-limiting examples of comparators include, butare not limited to, a negative control, a positive control, an expectednormal background value of the subject, a historical normal backgroundvalue of the subject, an expected normal background value of apopulation that the subject is a member of, or a historical normalbackground value of a population that the subject is a member of. Invarious embodiments, the disease or disorder is cancer, inflammation,macular degeneration. In some embodiments, the method of diagnosingincludes a further step of treating the patient for the diagnoseddisease or disorder.

In various embodiments, the subject is a human subject, and may be ofany race, sex and age. Representative subjects include those who aresuspected of having experienced a disease or disorder, those who havebeen diagnosed as having experienced a disease or disorder, those whohave been diagnosed as having a disease or disorder, and those who areat risk of developing a disease or disorder.

Information obtained from the methods of the invention described hereincan be used alone, or in combination with other information (e.g.,disease status, disease history, vital signs, blood chemistry, etc.)from the subject or from the biological sample obtained from thesubject.

In other various embodiments of the methods of the invention, the levelof VEGF detected by the synthetic polymers of the present invention isdetermined to be increased when the level of VEGF is increased by atleast 10%, by at least 20%, by at least 30%, by at least 40%, by atleast 50%, by at least 60%, by at least 70%, by at least 80%, by atleast 90%, by at least 100%, by at least 200%, by at least 300%, by atleast 400%, by at least 500%, by at least 600%, by at least 700%, by atleast 800%, by at least 900%, by at least 1000%, when compared to with acomparator control. In various embodiments, an increased level of VEGFis indicative of a disease or disorder.

In the methods of the invention, a biological sample from a subject isassessed for the level of VEGF using the synthetic polymers of thepresent invention. The level of VEGF in the biological sample can bedetermined by assessing the level of binding to the synthetic polymersof the present invention. In some embodiments, the level of VEGF in thebiological sample is determined in an assay using the synthetic polymersof the present invention.

In various embodiments, methods of measuring VEGF levels in a biologicalsample obtained from a patient include, but are not limited to, animmunochromatography assay, an immunodot assay, a Luminex assay, anELISA assay, an ELISPOT assay, a protein microarray assay, a Westernblot assay, a mass spectrophotometry assay, a radioimmunoassay (MA), aradioimmunodiffusion assay, a liquid chromatography-tandem massspectrometry assay, an ouchterlony immunodiffusion assay, reverse phaseprotein microarray, a rocket immunoelectrophoresis assay, animmunohistostaining assay, an immunoprecipitation assay, a complementfixation assay, FACS, an enzyme-substrate binding assay, an enzymaticassay, an enzymatic assay employing a detectable molecule, such as achromophore, fluorophore, or radioactive substrate, a substrate bindingassay employing such a substrate, a substrate displacement assayemploying such a substrate, and a protein chip assay.

EXPERIMENTAL EXAMPLES

The invention is further described in detail by reference to thefollowing experimental examples. These examples are provided forpurposes of illustration only, and are not intended to be limitingunless otherwise specified. Thus, the invention should in no way beconstrued as being limited to the following examples, but rather, shouldbe construed to encompass any and all variations which become evident asa result of the teaching provided herein.

Without further description, it is believed that one of ordinary skillin the art can, using the preceding description and the followingillustrative examples, make and utilize the compounds of the presentinvention and practice the claimed methods. The following workingexamples therefore, specifically point out exemplary embodiments of thepresent invention, and are not to be construed as limiting in any waythe remainder of the disclosure.

Example 1: Synthetic Polymer Protein Affinity Reagents. A PolymerNanoparticle with Engineered Affinity for a Vascular Endothelial GrowthFactor (VEGF₁₆₅)

The following study describes the synthesis of an abiotic hydrogelpolymer nanoparticle (NP) that has been engineered with affinity for akey vascular endothelial growth factor (VEGF₁₆₅), a signaling proteinthat stimulates angiogenesis. VEGF₁₆₅ is a 38 kD protein (pI 7.6) withbinding-domains for its receptor (VEGFR-2) and for heparin. Heparin, apolysulfated linear polysaccharide, contains repeating disaccharideunits of uronic acid and glucosamine moieties. Candidates with highaffinity to VEGF₁₆₅ were identified from a screen of polymer NPsincorporating sulfonic acid, sulfated carbohydrate and hydrophobicfunctional monomers in a 2% crosslinked NIPAm copolymer (FIG. 1A throughFIG. 1D). The process, described in detail below, identified a highaffinity functional NIPAm copolymer that both binds to and inhibits thefunction of VEGF₁₆₅. The results establish a novel path for developingabiotic affinity reagents for functional biomacromolecules.

The materials and methods used in the experiments are now described.

Materials

Mouse VEGF-A165, bovine serum albumin, N-isopropylacrylamide (NIPAm),N,N,N′,N′-tetramethylethylenediamine, and sodium dodecyl sulfate (SDS)were purchased from Sigma Aldrich. N,N′-methylenebisacrylamide (BIS) wasfrom Fluka; N-t-butylacrylamide (TBAm) was from ACROS ORGANICS.Anti-VEGF receptor-2 and anti-phospho-VEGF receptor-2 (Tyr 951) rabbitmonoclonal antibody (Cell Signaling Technology Inc., Beverly, Mass.,USA), anti-β-actin rabbit polyclonal antibody (Sigma-Aldrich), andHRP-conjugated anti-rabbit IgG polyclonal antibody (GE HealthcareBioscience, Tokyo, Japan) were purchased from the sources indicated.Each antibody was diluted according to the manufacturer's instructions.

Synthesis of GlcNAc Monomers

All aqueous solutions were prepared with ultrapure water (18 M cm⁻¹,Millipore System). H₂O was MilliQ water in all experiments. Thefollowing reagents were used as received: Benzaldehyde dimethyl acetal(PhCH(OMe)₂), chloroform-d for NMR, 99.8% atom % D, stabilized withsilver foil (CDCl₃), deuterium oxide, 99.8% atom % D (D₂O), methylsulfoxide-d₆ for NMR (DMSO-d₆), with 0.03% TMS, 99.9 atom % D,triethylsilane (Et₃SiH) (Acros Organics, Geel, Belgium), benzoylchloride (BzCl), diethyl ether (Et₂O), heparin sodium, methanol (MeOH),potassium carbonate (K₂CO₃), sodium hydrogen carbonate (NaHCO₃),trifluoroacetic acid (TFA) (Kanto Chemical, Tokyo, Japan), 10%palladium(II) carbon (Pd/C) (Kojima Chemicals, Saitama, Japan), sulfurtrioxide pyridine complex (SO₃—Py), sulfur trioxide trimethylaminecomplex (SO₃-NMe₃) (Sigma-Aldrich, Louisiana, Mo., USA), acryloylchloride, trifluoroacetic anhydride (TFAA) (TCI, Tokyo, Japan), sodiummethoxide (NaOMe) (Wako Chemical, Osaka, Japan).

Dowex 50WX8, 50-100 mesh, H form (DOW, Michigan, USA) was converted toNa form with 1N NaOH before use. p-toluenesulfonic acid monohydrate(p-TsOH) (TCI, Tokyo, Japan) was dried in vacuo before use.

p-Nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranoside (1) andp-(N-acrylamido)phenyl 2-acetamido-2-deoxy-6-sulfo-β-D-glucopyranoside12 were prepared from 2-acetamido-2-deoxy-β-D-glucopyranose describedpreviously (Chen, H. M. et al., Carbohydr Res (2007) 342:2212-22;Sasaki, K. et al., Bioorg Med Chem Lett (2003) 13:2821-3).p-(N-Acrylamido)phenyl β-D-glucuronide was prepared from p-nitrophenyl3-D-glucuronide described previously (Miura, Y. et al., Bulletin of theChemical Society of Japan (2010) 83:1004-1009). The following materialswere used as received: glass fiber filter (GF75, ADVANTEC, Ehime, JAPAN)

¹H NMR (400 MHz) and ¹³C NMR (100 MHz) spectra were recorded in CDCl₃,DMSO-d₆, D₂O at room temperature with a JNM-ECP400 (JEOL, Tokyo, Japan).Mass spectra were obtained in MeOH:H₂O=1:1 at room temperature with anESI-MS LCQ-DECA XP spectrometer (Thermo Scientific, Waltham, Mass.,USA).

Syntheses of Sulfated GlcNAc Monomers

p-Nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranoside (1): 1 wasprepared from 2-acetamido-2-deoxy-β-D-glucopyranose (GlcNAc) describedpreviously (Chen, H. M. et al., Carbohydr Res (2007) 342:2212-22;Sasaki, K. et al., Bioorg Med Chem Lett (2003) 13:2821-3).

p-Nitrophenyl 2-acetamido-4,6-O-benzylidene-2-deoxy-β-D-glucopyranoside(2):

Compound 1 (1.00 g, 2.92 mmol) was dissolved in dry DMF (30 mL).PhCH(OMe)₂ (530 μL, 3.50 mmol) and p-TsOH (80 mg, 0.438 mmol) were addedto the reaction mixture, and the mixture was stirred with a rotaryevaporator. The temperature of water bath was defined at 40° C. After 12h, the termination of the reaction was confirmed by TLC and RP-TLC(CHCl₃: MeOH=10:1, H₂O:MeOH=2:1, respectively). DMF was removed byevaporation. A saturated aqueous solution of sodium hydrogen carbonatewas added to the residue, and the mixture was stirred for 0.5 h at roomtemperature. The product was filtered off, washed with sufficientamounts of MilliQ water and diethyl ether, and dried in vacuo to afford2 (801 mg, 64%) as a white solid.

p-Nitrophenyl2-acetamido-4,6-O-benzylidene-3-sulfo-2-deoxy-β-D-glucopyranoside (3):Compound 2 (940 mg, 2.18 mmol) was dissolved in dry DMF (3 mL). SO₃-NMe₃(1.52 g, 10.91 mmol) was added to the solution and the reaction stirredat 40° C. for 72 h. The reaction was quenched by addition of MeOH (20mL). DMF was removed by evaporation, and purified by flush columnchromatography on silica gel with an eluent of (CHCl₃:MeOH=10:1 to 4:1).The eluate was evaporated and the residue was afforded 3 (894 mg, 72%)as a white solid.

p-(N-Acrylamido)phenyl 2-acetamido-2-deoxy-3-sulfo-D-glucopyranoside(4): Compound 3 (894 mg, 1.57 mmol) was dissolved in H₂O:MeOH=1:19 (15mL). Pd/C (90 mg) and concentrated hydrochloric acid (cHCl, 35-37 wt %solution, 681 μL, 7.85 mmol) were then added. The flask was placed in ahigh pressure vessel which was then pressurized with hydrogen. After 24h, the termination of the reaction was confirmed by TLC (H₂O:MeOH=4:1).Pd/C was removed by filtration with glass fiber filter (GF-75, Advantec,Tokyo, Japan) and the filtrate was evaporated to afford white solid. Theresidue was dissolved in THF:H₂O=1:2 (15 mL), cooled at 0° C., and tothe solution were added acryloyl chloride (190 μL, 2.36 mmol) and K₂CO₃(65 1 mg, 4.71 mmol). After stirring 5 minutes, the reaction solutionwas warmed up to room temperature. The termination of the reaction wasconfirmed by TLC (H₂O:MeOH=4:1). After 12 h, the reaction mixture wasneutralized with 1M HCl, evaporated, and purified by reverse-phasechromatography with an eluent of H₂O:MeOH=6:1. Eluent fractions wereion-exchanged to Na salt with ion-exchange resin. The solution wasfreeze dried to afforded 4 (182 mg, 25% in 3 steps) as a white powder.

p-Nitrophenyl2-acetamido-3-O-benzoyl-4,6-O-benzylidene-2-deoxy-β-D-glucopyranoside(5): Compound 2 (1.06 g, 2.46 mmol) was dissolved in pyridine (15 mL)solution, and BzCl (858 μL, 7.39 mmol) were added to the solution at 0°C. The mixture was stirred at room temperature, and the termination ofthe reaction was confirmed by TLC (CHCl₃:MeOH=10:1). After 15 h, thereaction mixture was quenched by MeOH (10 mL), and the solvent wasevaporated. The residue was purified by flush column chromatography onsilica gel with an eluent of (CHCl₃:MeOH=100:1). The white powder wasafforded 5 (1.34 g, >99%).

p-Nitrophenyl2-acetamido-3-O-benzoyl-6-O-benzyl-2-deoxy-4-hydroxy-β-D-glucopyranoside(6): 5 (297 mg, 0.556 mmol) was suspended in CH₂Cl₂ (4 mL) added TFAA(232 μL, 1.67 mmol) and Et₃SiH (444 μL, 2.78 mmol) at 0° C. Afterstirring for 15 minutes, TFA (207 μL, 2.78 mmol) was added dropwise andstirred 10 minutes. The reaction mixture was allowed to be warmed up tothe ambient temperature. After stirring for overnight, the terminationof the reaction was confirmed by TLC (EtOAc:Hexane=1:1). The reactionmixture was diluted by EtOAc and the organic layer was washed NaHCO₃,H₂O, and brine, respectively. The organic layer was dried on MgSO₄,filtrated, and the filtrate was evaporated. The residue was purified byflush column chromatography on silica gel with an eluent ofEtOAc:Hexane=1:1 and afforded 6 (260 mg, 87%) as a white solid.

p-Nitrophenyl2-acetamido-3-O-benzoyl-6-O-benzyl-2-deoxy-4-sulfo-β-D-glucopyranoside(7): The mixture of SO₃-NMe₃ (1.30 g, 9.32 mmol) in dry DMF (10 mL) wasadded dropwise to the flask of 6 (50 mg, 0.093 mmol) at 40° C. and thereaction mixture was stirred for 56 h. SO₃-NMe₃ (777 mg, 5.58 mmol) wasadded and stirred. After 28 h, reaction temperature was warmed to 50° C.and stirred for 17 h. The reaction was confirmed by TLC(CHCl₃:MeOH=3:1), and MeOH (30 mL) was added to the reaction mixture.The mixture was evaporated and the residue was purified by columnchromatography on RP-silica gel (Merck, Darmstadt, Germany) with aCHCl₃:MeOH=19:1 to 4:1. The white solid was afforded 7 (1.16 g, 92%).

p-(N-Acrylamido)phenyl2-acetamido-6-O-benzyl-2-deoxy-4-sulfo-β-D-glucopyranoside (8): 7 (923mg, 1.37 mmol) was dissolved in MeOH (25 mL). NaOMe was added to adjustto pH 10. The termination of the reaction was confirmed with TLC(CHCl₃:MeOH=7:3). After 12 h, the reaction was completed and neutralizedby Amberlyst (Organo Corporation, Tokyo, Japan). The reaction mixturewas filtered, and the filtrate was evaporated. The residue wasprecipitated with the EtOAc. The white powder was afforded 8 (739 mg,94%).

p-(N-Acrylamido)phenyl 2-acetamido-2-deoxy-4-sulfo-β-D-glucopyranoside(9): Pd/C (105 mg) and cHCl (0.1 mL) were added to the H₂O:MeOH=1:1 (30mL) solution of 8 (708 mg, 1.24 mmol). The hydrogenation was processedwith the autoclave reactor under high hydrogen pressure. After 24 h, thetermination of the reaction was confirmed by TLC (CHCl₃:MeOH=7:3). Pd/Cwas removed by filtration with a glass fiber filter and the filtrate wasevaporated to afford white solid. The residue was dissolved inTHF:H₂O=1:2 (12 mL), and cooled at 0° C. To the solution were addedacryloyl chloride (150 μL, 1.86 mmol) and K₂CO₃ (514 mg, 3.72 mmol).After stirring 5 minutes, the reaction mixture was allowed to be warmedup to the ambient temperature. The termination of the reaction wasconfirmed by TLC (H₂O:MeOH=4:1). After 20 h, the reaction mixture wasneutralized with 1M HCl, evaporated, and purified by reverse-phasechromatography with a H₂O:MeOH=3:1. Eluent fractions were ion-exchangedto Na salt with ion-exchange resin. The solution was freeze dried andpurified by reverse-phase chromatography with an eluent of H₂O:MeOH=8:1.The solution was freeze dried and afforded 9 (264 mg, 42% in 3 steps) asa white powder.

Preparation of 3,4,6-sulfo GlcNAc monomer 11

p-Nitrophenyl 2-acetamido-2-deoxy-3,4,6-sulfo-β-D-glucopyranoside (10):1 (500 mg, 1.46 mmol) was dissolved in pyridine, and to the solution wasadded SO₃-Py (2.32 g, 14.6 mmol). The termination of the reaction wasconfirmed by TLC (CHCl₃:MeOH=1:1). After 144 h, MeOH (30 mL) was added.The reaction mixture was passed through an ion-exchange column. Theeluent fractions were evaporated, and the residue purified columnchromatography on RP-silica gel (H₂O:MeOH=9:1). After evaporation ofeluent fractions the residue was ion-exchanged to Na salt. The solutionwas evaporated and freeze dried to afford 10 (938 mg, 99%) as a whitepowder.

p-(N-Acrylamido)phenyl2-acetamido-2-deoxy-3,4,6-sulfo-β-D-glucopyranoside (11): 10 (860 mg,1.33 mmol) was dissolved in a mixture of H₂O:MeOH=1:1 (50 mL). To thesolution were added Pd/C (90 mg) and CHCl (0.1 mL). The hydrogenationwas performed with an autoclave under high hydrogen pressure. After 25h, the termination of the reaction was confirmed by RP-TLC(H₂O:CH₃COOH=95:5). Pd/C was removed by filtration with a glass fiberfilter, and the filtrate was evaporated to afford a white solid. Theresidue was dissolved in a mixture of THF:H₂O=1:2 (10 mL), cooled at 0°C., and to the solution was added acryloyl chloride (176 μL, 2.18 mmol)and K₂CO₃ (601 mg, 4.35 mmol). After stirring 5 minutes, the reactionmixture was allowed to be warmed up to the ambient temperature. After 12h, the termination of the reaction was confirmed by RP-TLC(H₂O:CH₃COOH=95:5). The reaction solution was neutralized with 1M HCl,evaporated. The residue was purified by column chromatography onRP-silica gel with an eluent of H₂O:MeOH=9:1. The residue was dissolvedin H₂O and freeze dried and afforded 11 (1.07 g, >99% in 2 steps) as awhite powder.

p-(N-Acrylamido)phenyl 2-acetamido-2-deoxy-6-sulfo-β-D-glucopyranoside(12): 12 were prepared starting from2-acetamido-2-deoxy-β-D-glucopyranose was described previously (Chen, H.M. et al., Carbohydr Res (2007) 342:2212-22; Sasaki, K. et al., BioorgMed Chem Lett (2003) 13:2821-3).

p-(N-Acrylamido)phenyl β-D-glucuronic acid (13): 13 was preparedstarting from p-nitrophenyl β-D-glucuronide was described previously(Miura, Y. et al., Bulletin of the Chemical Society of Japan (2010)83:1004-1009).

Preparation of NPs

NPs were synthesized of by free-radical copolymerization ofN-isopropylacrylamide (NIPAm) cross-linked with 2 mol %N,N′-methylenebisacrylamide (Bis). N-t-butylacrylamide (TBAm) and3-sulfo-N-acetylglucosamines (3S), 4-sulfo-N-acetylglucosamines (4S),6-sulfo-N-acetylglucosamines (6S) or 3,4,6-sulfo-N-acetylglucosamines(3,4,6S) were used as hydrophobic and negatively charged functionalmonomers. NIPAm (98-(W+X+Y+Z) mol %), NIPAm (W mol %), GlcNAc (X mol %),TBAm (Y mol %), BIS (2 mol %), and SDS (10 mg) were dissolved in water(50 mL) and the resulting solutions were filtered through a no. 2Whatman filter paper. TBAm (Z mol %) was dissolved in ethanol (1 mL)before addition to the monomer solution, which resulted in a totalmonomer concentration of 6.5 mm. The resulting solutions were degassedin a sonication bath under vacuum for 10 min and then nitrogen wasbubbled through the reaction mixtures for 30 min. Following the additionof ammonium persulfate aqueous solution (30 mg per 500 μL), thepolymerization was carried out at 65° C. for 3 h under a nitrogenatmosphere. The polymerized solutions were purified by dialysis againstan excess amount of pure water (changed more than twice a day) for >4days.

Characterization of NPs

The hydrodynamic diameter of NPs was determined in aqueous solution bydynamic light scattering (DLS) (Zetasizer Nano ZS). The temperature ofthe NP samples was controlled via Peltier device at 25±0.1° C. Yield andconcentration of NPs was determined by measuring weight of NP afterlyophilization.

Quantification of GlcNAc Monomers in NPs by 1H-NMR

In order to determine the ratio of TBAm, NIPAm, and GlcNAc in thepolymer, ¹H NMR spectroscopy was utilized using an acquisition time of30 seconds, respectively. NMR spectra were acquired in CD3OD and thechemical shifts are reported in ppm on the δ scale reference to residualCD2HOD (δ 3.31 ppm). The incorporation ratio of GlcNAc and TBAm to NIPAmin the polymer was calculated from the integration of the methyl protonresonances at 1.36 (Tp), 1.16 ppm (Np), 6.99 ppm (Gp) using the equationTBAm:NIPAm:GlcNAc=(Tp/9):(Np/6):(Gp/2).

For all of the samples analyzed, integration of the signals of themethyl proton of the benzene, tert-butyl and isopropyl groups from theNMR spectroscopic data was consistent with the feed ratio. Although noanalytical data could be obtained to quantify the incorporation of BISin the polymer, it was assumed that the feed ratio of the BIS (Bfeed) toother acrylamide monomers prior to polymerization reflected theincorporation ratio of these monomers in the polymer, becauseincorporation ratio of other amides (GlcNAc, TBAm and NIPAm) wereconsistent with the feed ratio. This relationship was used toapproximate the incorporation of GlcNAc in all of the NPs synthesized inthis study (FIG. 1A through FIG. 1D).

Quartz Crystal Microbalance (QCM) Analysis

An Affinix Q⁴ QCM instrument (Initium Co. Ltd., Tokyo, Japan) was usedto quantify interactions between the NPs and proteins. At first, goldelectrodes were cleaned with piranha solution for 5 min, twice.3,3′-Dithiodipropionic acid (1 mM, 0.1 mL) was added into the QCM cellsand incubated for overnight. Then, the QCM cells were washed with purewater and carboxylic acids on electrodes were activated by loading of1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (100 mg/ml) andN-hydroxysuccinimide (100 mg/mL) 1:1 aqueous solution (0.1 mL) to formN-hydroxysuccinimidyl esters. Protein solutions were loaded on the cellsto give protein-immobilized cells.

For immobilization of mouse VEGF₁₆₅, the proteins (30 μg/mL) diluted bydH₂O was added onto QCM gold surface (10 μL) and incubated for 3 h at37° C. Then, the QCM cells were washed with pure water for 2 times, andblocked with 1 mg/mL BSA solution for 1 h. NPs were added into the cellsat concentrations of 1.99, 5.9, 13.6, 28.3, 55.2, 100.6, and 168.43μg/ml. Interactions between NPs and proteins were observed at (37±0.1°)C. in PBS (pH 7.4). The apparent dissociation constant of NPs to proteinwas calculated under the assumption that all particles have the sameaffinity to protein.

Cell Culture

Human umbilical vein endothelial cells (HUVECs, Takara Bio Inc., Otsu,Shiga, Japan) were maintained in endothelial growth medium-2 (EGM-2,Cambrex Corporation, Walkersville, Md., USA) at 37° C. under 5% CO₂ in ahumidified chamber.

Cell Proliferation and Cytotoxicity Assay

HUVECs were treated with NPs and VEGF₁₆₅ (20 ng/mL) for 48 h. TetracolorONE™ (Seikagaku, Tokyo, Japan) was added to each well in accordance withthe manufacturer's instructions. The amount of formazan was measuredwith a Tecan Infinite M200 micro plate reader at a test wavelength of450 nm and a reference wavelength of 630 nm.

Western Blotting

HUVECs were seeded onto 6 well plates at a density of 2×10⁵ cells/welland incubated overnight. The culture medium was then changed to EBM-2without growth factors and serum. Twelve hours after the medium change,cells were incubated with EBM-2 containing 20 ng/mL of VEGF₁₆₅ anddifferent concentration of NPs for 2 h at 37° C. For negative control,cells were incubated with only EBM-2 (no VEGF₁₆₅ and NPs). The cellswere then washed with PBS and lysed with lysis buffer composed of 10 mMTris (pH 7.5), 0.1% SDS, 50 μg/mL aprotinin, 200 μM leupeptin, 2 mMPMSF, 100 μM pepstatin A and 1 mM Na₃VO₄. The total proteinconcentration was measured by using a BCA Protein Assay Reagent Kit(PIERCE Biotechnology, Rockford, Ill.). The cell extracts were subjectedto 7.5% SDS-PAGE and transferred electrophoretically to polyvinylidenedifluoride (PVDF) membranes (Millipore, Billerica, Mass., USA). Afterhaving been blocked for 1 h at room temperature with 5% BSA inTris-HCl-buffered saline containing 0.1% Tween 20 (TTBS, pH 7.4), themembranes were incubated with a primary antibody (against β-actin, VEGFreceptor-2 or pVEGF receptor-2 [Tyr 951]) for 24 h at 4° C. Themembranes were then incubated for 1 h at room temperature withHRP-conjugated secondary antibody at a dilution of 1:2000. Each samplewas developed by using a chemiluminescent substrate (ECL; GE HealthcareBioscience), and each protein was detected with the LAS-3000 minisystem.

Cell Proliferation and Cytotoxicity Assay

HUVECs were seed on gelatin-coated 96 well plate at 5.0×10³ cells/welland incubated overnight. Then, the culture medium was changed toendothelial basal medium-2 (EBM-2, Clonetics) without fetal bovine serum(FBS, Clonetics) and growth factors. Twelve hours after the changing ofmedium, the cells were treated with NPs and VEGF₁₆₅ (20 ng/mL) for 48 h.For cytotoxicity assay, the cells were treated with only NPs for 48 h.Finally, Tetracolor ONE™ (Seikagaku, Tokyo, Japan) was added to eachwell in accordance with the manufacturer's instructions. The amount offormazan formed in 3 h was measured with a Tecan Infinite M200 microplate reader at a test wavelength of 450 nm and a reference wavelengthof 630 nm.

Motility and Invasion Assays

HUVECs in serum-free EBM-2 were fluorescently labeled with 3 mM3′-O-acetyl-2′-7′-bis(carboxyethyl)-4 or 5-carboxyfluorecein,diacetoxymethylester (BCECF-AM, Dojindo Laboratories, Kumamoto, Japan)for 30 min at 37° C. and then washed with PBS. The cells (5×10⁴ cells in300 mL of EBM-2) were applied to a FALCON HTS FluoroBlok™ Insert (BD,Franklin, Lakes, N.J., U.S.A.), non-coated for the motility assay orpre-coated with BD Matrigel (125 mg/insert, BD) for the invasion assay.Each culture insert was set into a well containing 700 mL of EBM-2supplemented with VEGF₁₆₅ (20 ng/mL) with or without NPs (30 μg/mL). Theinserts were incubated for 24 h at 37° C. After the incubation, theFluoroBlok membrane was picked up and placed on a glass slide, and thecells that invaded to the lower side of the membrane were observed undera fluorescence microscope (IX71, Olympus, Tokyo, Japan) equipped with aCCD camera (Penguin 600CL, Pixera, Osaka, Japan).

Capillary Tube Formation Assay

Matrigel (BD Biosciences Bedford, Mass.) was diluted to 4 mg/mL withEBM-2 added to 24-well culture plates, and allowed to undergopolymerization. HUVECs were seeded onto Matrigel coated plate at theconcentration of 5×10⁴ cells/well. Then, the HUVECs were added VEGF₁₆₅(20 ng/mL) or/and NPs (30 μg/mL) and were incubated for 12 h at 37° C.Photographs were taken with an Olympus IX71 microscope.

Experimental Animals and In Vivo Matrigel Plug Assay

Five-week-old BALB/c male mice were purchased from Japan SLC Inc.(Shizuoka, Japan). BALB/c-male mice (n=3) were subcutaneously injectedwith a liquid Matrigel (6 mg/mL) diluted by PBS (700 μL/mouse). TheMatrigel contained 20 nM mouse VEGF₁₆₅ and 42 Units of heparin(Ajinomoto Pharmaceuticals Co., Ltd Japan) to stimulate angiogenesis,and NPs at a final concentration of 300 μg/mL. Matrigel and PBS or mouseVEGF₁₆₅ and heparin were injected as negative and positive controls,respectively. After 10 days, Matrigel plugs were removed andphotographed. To measure the hemoglobin in the Matrigel, the Matrigelwas diluted by PBS and homogenized. The homogenized Matrigel (30 μL) wasincubated with 95% glacial acetic acid (120 μL) for 20 min. After theincubation, the sample was centrifuged (5 min, 5000×g) and 30 μL ofsupernatant was added to 120 μL of 5 mg/mL3,3′,5,5′-tetramethylbenzidine (TMB, Sigma) diluted with 95% glacialacetic acid. Hydrogen peroxide (150 μl of 0.3%, Sigma) was added to eachwell and the absorbance was measured with a Tecan Infinite M200 microplate reader at 600 nm.

Statistical Analysis

Differences in a group were evaluated by an analysis of variance (ANOVA)with the Tukey post hoc test.

The results are now described.

Synthesis of Sulfonated and Sulfated Monomers and their Incorporationinto Polymer Nanoparticles

The strategy employed was to identify several domains of VEGF₁₆₅ andsynthesize NPs that incorporate complimentary functional monomers tointeract with those domains. Although no structural information of theVEGF₁₆₅-heparin complex is available, Arg 124, 145, 149 and 159 in theVEGF₁₆₅ sequence are known to play a crucial role in heparin binding(Robinson, C. J. et al., J Biol. Chem. (2006) 281:1731-1740). Thispositive charge-rich domain is spread over 40 nm². To target thisdomain, a series of polymerizable sulfonated and sulfated monomers wereprepared. The monomers include 2-acrylamido-2-methylpropane sulfonicacid (AS), three positional isomers of mono-sulfatedN-acetylglucosamines (3 S-GlcNAc, 4S-GlcNAc, 6S-GlcNAc) and atri-sulfated N-acetylglucosamine (3,4,6S-GlcNAc). Their structures areshown in FIG. 1B. Solutions of polymer NPs were prepared by a modifiedprecipitation polymerization and purified by extensive dialysis. Each NPcontained one of the anionic monomers, in addition toN-isopropylacrylamide (NIPAm), N-tert-butylacrylamide (TBAm, ahydrophobic monomer), and 2% N, N′-methylenebisacrylamide (Bis, acrosslinker) (FIG. 1A). Inclusion of the hydrophobic TBAm monomer wasbased upon crystallographic studies of the VEGF-VEGFR2 binding surfacewhich has a number of hydrophobic amino acids that play an importantrole in VEGFR binding (Brozzo, M. S. et al., Blood (2012) 119:1781-1788)and previous studies that established the importance of hydrophobiccontent of the NP for protein affinity (Hoshino, Y. et al. P Natl AcadSci USA (2012) 109:33-38; Lee, S. H. et al., J. Am. Chem. Soc. (2012)134:15765-15772; Yoshimatsu, K. et al., Angew. Chem. Int. Ed. (2012)51:2405-2408; Hoshino, Y. et al., Small (2009) 5:1562-1568; Hoshino, Y.et al., J. Am. Chem. Soc. (2010) 132:6644-6645). Summaries of NPcomposition, particle size, -potential, chemical yield and incorporationpercentage of the anionic monomers (NMR analysis) are given in FIG. 2Athrough FIG. 2E and FIG. 3A through FIG. 3D. The monomodal hydrogelparticles ranged in size from 30-90 nm. FIG. 1C and FIG. 1D arerepresentative TEM images of the monodisperse synthetic NPs.

Evaluation of NP Affinity to VEGF₁₆₅

A quartz crystal microbalance (QCM) sensor functionalized with VEGF₁₆₅was used to screen the NP library for protein binding. Interestingly,none of the NPs containing the negatively charged sulfonate group (AS)(NPs 2-4) showed significant binding to VEGF₁₆₅ even when the amount ofAS in the NP was increased to 10% (FIG. 4A). Next, NPs containing the 3S-GlcNAc, 4S-GlcNAc or 6S-GlcNAc (mono-sulfated GlcNAc monomers, NPs5-10), and the 3,4,6S-GlcNAc (tri-sulfated GlcNAc monomer, NPs 11-13)were screened. These NPs exhibited a wide range of VEGF₁₆₅ interaction.Among NPs 5, 7 and 9 (1.7% of mono-sulfated monomer), only NP5 (1.7%3S-GlcNAc) exhibited modest VEGF₁₆₅ interaction (FIG. 4B). NPs 6, 8 and10 (5% of these same mono-sulfated monomers) showed much lowerinteraction with the protein (FIG. 4C). Collectively, the resultsestablish that NP binding to VEGF₁₆₅ is dependent on the nature of thecharged group (sulfate vs sulfonate), the GlcNAc scaffold and theposition of sulfation (3′ vs 4′ or 6′). The sensitivity to thepositional isomers on the carbohydrate skeleton may not be surprising asthere are a number of studies that report the importance of sulfateposition on affinity to target proteins. For example, the 3-O-sulfogroup within heparin has been reported to be essential for binding toantithrombin III (Richard, B. et al., J Biol. Chem. (2009)284:27054-27064), the fibroblast growth factor (FGF)-7 (Ye, S. et al.,Biochemistry (2001) 40:14429-14439) and the 6-O-sulfo groups for bindingto FGF-1 (Guimond, S. et al., J Biol. Chem. (1993) 268:23906-23914).

The screen of NPs 11-13 incorporating the showed far more dramaticresults. Although the particle size and -potential of NPs 11-13 were notsignificantly different from other NPs tested (FIG. 2A through FIG. 2E),NP11 strongly interacted with VEGF₁₆₅ (FIG. 4D). The observed frequencychange (up to 1200 Hz) was 6 times higher than that of NPS. A controlstudy confirmed that the NPs in this study do not interact with theblocking agent (bovine serum albumin, BSA) (FIG. 5A). NP11 affinity isestimated to be ˜380 nM (QCM) (FIG. 5B). This result suggests that smalllocal clusters of negative charge from the 3,4,6S-GlcNAc monomer areimportant for NP binding to VEGF₁₆₅. The significance of hydrophobicgroups (TBAm) was established by observing that decreasing the TBAmcontent of NPs containing 1.7% of the 3,4,6 tri-sulfated GlcNAc monomerfrom 40% (NP11) to 20% (NP14) to 0% (NP15) significantly reduced andeventually eliminated the interaction with VEGF₁₆₅ (FIG. 6A and FIG.6B), suggesting that in addition to localized multipoint electrostaticinteractions, hydrophobic content is an essential component for theNP11-VEGF₁₆₅ interaction.

As stated previously, Arg 124, 145, 149 and 159 in the VEGF₁₆₅ sequenceare known to play a crucial role in heparin binding (Robinson, C. J. etal., J Biol. Chem. (2006) 281:1731-1740). It was speculated that NPsincorporating clusters of negative charge, such as the multiple sulfated3,4,6S GlcNAc group, are effective at binding to this positively chargeddomain of VEGF₁₆₅. Validation that a significant component of theinteraction between VEGF₁₆₅ and NP11 is at the heparin-binding domaincomes from QCM studies with VEGF₁₂₁, a truncated growth factor thatlacks the heparin-binding domain. NP11 shows little affinity for thisprotein (FIG. 7). This result coupled with the TBAm results point to theimportance of cooperative interactions to realize NP-protein affinity.

That the clustered charge of the tri-anionic monomer may also contributeto the NP-protein affinity comes from comparison with NPs containing anequivalent amount of charged groups using singly charged monomers. TheseNPs would be less likely to create a “cluster” of negative charge due toelectrostatic repulsion of the negative charges in the polymerizationstep. The constrained triply charged monomer does not suffer from thiseffect. So, although the net charge of 5% mono-sulfate NPs (NPs 6, 8,10) and 1.7% 3,4,6S NPs (NP11) is the same, the local presentation ofcharge in the NP may be significantly different and may be acontributing factor to the difference in affinity. However, these trendsare not expected to manifest themselves in zeta potential measurements.A decrease of zeta potential with increase of surface charge density hasbeen observed previously and explained by an ion condensation model. Itwas predicted theoretically and shown experimentally that for asufficiently high surface charge density, nearby counter ions cancollapse on the particle or polyelectrolyte lowering the effectivemagnitude of the particle zeta potential (Manning, G. S., Acc. Chem.Res. (1979) 12:443-449; Quesada-Perez, M. et al., J Colloid InterfaceSci (2001) 233:280-285; Manning, G. S., Ber Bunsen Phys Chem (1996)100:909-922; Popov, A. et al., J Polym Sci Pol Phys (2004) 42:3616-3627;Manning, G. S., J Phys Chem B (2007) 111:8554-8559).

Interestingly, both NP12 and NP13 containing a higher percentage oftrisulfate monomer 3,4,6S-GlcNAc (5 or 10%) had substantially lowerprotein interaction compared to NP11. This would appear to be aconsequence of the complexity of protein surfaces and the sensitivity tothe exact (average) composition of the affinity reagent. In addition tothe heparin-binding domain, VEGF₁₆₅ has a number of negatively chargedamino acids on its surface. The diminished interaction for VEGF₁₆₅ ofNP12 (5%, 3,4,6S-GlcNAc) compared to NP11 (1.7% 3,4,6S-GlcNAc) reflectsa needed balance of electrostatic interactions between the proteinsurface and NP; a higher loading of the tri-anionic 3,4,6S-GlcNAceventually results in repulsion between the protein and NP. Thissensitivity to both charge and hydrophobic contributions calls attentionto the uniqueness of each protein (and NP) domain, an attribute that isresponsible in part for the selectivity of protein-protein binding insignal transduction and related phenomena.

In Vitro VEGF-Inhibition Experiments and Comparison with Heparin

Binding of VEGF₁₆₅ to VEGFR-2, its native receptor, is known to inducethe phosphorylation of VEGFR-2 and trigger downstream cell signalingevents (Graells, J. et al., J Invest Dermatol. (2004) 123:1151-1161).Although there is no direct evidence for the interaction of NP11 withthe VEGFR-2 binding domain of VEGF₁₆₅, it was speculated that binding ofthis relatively large multifunctional NP (˜85 nm) with the protein (<10nm) could antagonize binding to VEGFR-2. An in vitro study was carriedout to confirm the inhibitory effect of NP11 on VEGF₁₆₅-inducedphosphorylation of VEGFR-2. Human umbilical vein endothelial cells(HUVEC) were incubated with the VEGF₁₆₅ at several concentrations ofNPs. NP11 strongly inhibited the phosphorylation (Tyr₉₅₁) at aconcentration of 10 μg/mL (FIG. 8A), whereas NP1, NP12 or NP13 did notinhibit the phosphorylation of VEGFR-2 at 100 μg/mL (FIG. 9A throughFIG. 9C). It was concluded that NP11 inhibits VEGFR-2 phosphorylation bysequestering VEGF₁₆₅. Phosphorylation of VEGFR-2 is the signaling eventfor endothelial cell growth. To evaluate the influence of NPs onVEGF₁₆₅-dependent cell growth, VEGF₁₆₅ and NPs were added onto HUVEC.NP11 dose-dependently inhibited VEGF₁₆₅-dependent cell growth, a resultthat correlates with the phosphorylation inhibition results (FIG. 8B).Indeed, the half maximal inhibitory concentration (IC₅₀) ofVEGF₁₆₅-dependent HUVEC growth by NP11 was approximately 5 μg/mL. At aconcentration of 10 μg/mL, the growth rate was approximately equal tothat of control cells without VEGF₁₆₅ (FIG. 8B). These results establishthat 10 μg/mL of NP11 effectively inhibits VEGF₁₆₅-dependentphosphorylation and subsequent downstream cell proliferation.Importantly, NP11 was not taken up into the HUVEC even when the NPconcentration was increased to 300 μg/ml (FIG. 10).

Unfractionated heparin (UFH) or low molecular weight heparin (LMWH,dalteparin) also bind to VEGF₁₆₅. However, these sulfated carbohydratesbind to a number of functional proteins and produce a number of offtarget outcomes. Perhaps the most important of which is theiranti-coagulant activity. For example, following binding of heparin toantithrombin III (AT III), factor Xa (FXa), a key enzyme in the bloodcoagulation cascade, binds to the complex and induces anti-coagulation.Since NP11 has affinity to the heparin-binding domain of VEGF₁₆₅ it isimportant to establish if the NP exhibits other heparin-like properties.Significantly, it was found that NP11 does not inhibit the activity ofFXa (FIG. 8C). On the other hand, FXa's function was inhibited byheparins. Even at a concentration of 100 μg/mL, NP11 exhibited noinhibition of FXa. The observation demonstrates that although NP11selectively inhibits VEGF₁₆₅-dependent activity by multiple interactionswith both heparin and VEGFR binding domains, it does not interfere withthe coagulation cascade. These same studies also established that NP11did not exhibit cytotoxicity in the range of 0-100 μg/mL (FIG. 11).Since there is little homology in heparin binding domains (Munoz, E. M.et al., Arterioscl Throm Vas (2004) 24:1549-1557), these resultsdemonstrate a potential path to selective abiotic affinity reagents forproteins with heparin binding domains or heparin-mediated processes.

UFH or LMWH also showed a dose-dependent inhibition of VEGF₁₆₅-dependentHUVEC growth (FIG. 8D) with an IC₅₀ of 1 μg/mL and 0.3 μg/mL for UFH andLMWH, respectively. However, in contrast to NP11, at thoseconcentrations both UFH and LMWH strongly inhibit FXa, and interferewith the clotting cascade which would result in undesired side effectsupon administration (FIG. 8C) (Oh, Y. I. et al., Angew. Chem. Int. Ed.(2013) 52:11796-11799; Warkentin, T. E. et al., N Engl J Med. (1995)332:1330-1335). These results establish that NP11 is not a heparin mimicand does not exhibit an important heparin function. Its action cannot bereplaced by heparin or its derivatives.

Anti-Angiogenic Effect of NPs

VEGF₁₆₅ is known to play a major role in angiogenesis and is a criticalfactor during the early stages of tumor growth (Karamysheva, A. F.,Biochemistry (Mosc) (2008), 73:751-762; Carmeliet, P. et al., Nature(2000) 407:249-257; Brekken, R. A. et al., Cancer Res (2000)60:5117-5124). In angiogenesis, endothelial cell migration and invasioninto the extracellular matrix are important steps in the production ofangiogenic blood vessels. The effect of NP11 on downstream angiogenicactivity was evaluated by experiments that revealed only NP11 (30 μg/mL)significantly inhibits VEGF₁₆₅-induced HUVECs migration and invasion(FIG. 12A, FIG. 13A through FIG. 13C). In addition, tube formation byendothelial cells is the first step in formation of angiogenic bloodvessels. HUVECs were seeded onto a Matrigel coated plate and thenVEGF₁₆₅ (20 ng/mL) and NPs (30 μg/mL) were added to the medium. HUVECsformed capillary-like structures only upon addition of VEGF₁₆₅. However,the addition of NP11 effectively inhibits the VEGF₁₆₅-induced capillarytube formation (FIG. 12B, FIG. 14). On the other hand, capillary tubeformation was not inhibited by NPs with less pronounced VEGF₁₆₅ affinitysuch as NP1, NP12 or NP13. The inhibition of downstream anti-angiogenicfunction is a consequence of the sequestration of VEGF₁₆₅ by NP11.

To evaluate the efficacy of NP11 to block new blood vessel formationunder more challenging conditions, a Matrigel plug assay was performed.Mice were subcutaneously injected with Matrigel alone, a VEGF₁₆₅/heparin(positive control), or VEGF₁₆₅/heparin and NP11. Ten days after theimplantation, Matrigel plugs were removed and the hemoglobin content wasmeasured. As shown in FIG. 12C, incorporation of NP11 into the Matrigelplug effectively inhibited blood vessel formation. Indeed, thehemoglobin content in the Matrigel plug was very close to that of thenegative control (absence of VEGF₁₆₅, FIG. 12D). Collectively, theseresults establish the ability of NP11 to inhibit recruitment ofendothelial cells and prevent new blood vessel formation bysequestrating VEGF₁₆₅.

The present study describes a process for synthesizing an abioticprotein affinity reagent. Polymer NPs with affinity for VEGF₁₆₅, a keyvascular endothelial growth factor, were identified from a screen of asmall library of NPs prepared by copolymerizing monomers withfunctionality complementary to the heparin and VEGFR-2 binding domainsof the protein. Polymer NPs with nanomolar affinity to VEGF₁₆₅ wererealized by incorporating 1.7% of a trisulfated N-acetylglucosamine(3,4,6S-GlcNAc) monomer, a hydrophobic group, N-tert-butylacrylamide(TBAm), in a 2% crosslinked NIPAm copolymer. NP affinity was “tuned” byvarying the amount of both 3,4,6S-GlcNAc and TBAm monomer incorporationsince increasing the 3,4,6S-GlcNAc monomer and/or decreasing thehydrophobic monomer (TBAm) content decreased affinity to the protein.The NP-protein interaction was designed to take place over multipleprotein domains (FIG. 15A through FIG. 15D), a factor that was validatedby compositional variation of the NP and by screening NP affinityagainst truncated proteins. The optimized NP (NP11) was shown to inhibitVEGF₁₆₅-dependent growth, tube formation, migration and invasion ofHUVECs in vitro through suppression of VEGFR-2 phosphorylation.Importantly, at concentrations needed to inhibit VEGFR-2phosphorylation, the optimized NP (NP11) did not inhibit the activity ofFXa. This result distinguishes the NP from heparin and its derivativesboth of which inhibit VEGF-dependent HUVEC growth in addition to enzymesinvolved in the blood coagulation cascade. NP11 was also shown toinhibit VEGF₁₆₅-dependent angiogenesis in a Matrigel plug in the body ofliving mice. These results establish that NPs can be engineered to bindto and interfere with a signaling protein (VEGF₁₆₅), by targetingspecific domains of the protein by inclusion of both hydrophobic and anovel trisulfated carbohydrate functional group into a 2% crosslinkedNIPAm synthetic polymer. The carbohydrate platform permits thestereocontrolled incorporation of clusters of functional groups, afeature not available to amino acid side chains. These results establishthe potential for realizing abiotic protein affinity reagents with manyof the functions of more traditional protein affinity reagents.

Example 2: An Abiotic Anti-VEGF Nanoparticle for Anti-Angiogenic CancerTherapy

Tumors require the induction and maintenance of a dedicated blood supplyfor their growth. Cancer cells secrete a number of growth factorsincluding vascular endothelial growth factor (VEGF) to create new bloodvessels in a process known as angiogenesis (Folkman, J., N Engl J Med(1971) 285(21):1182-1186; Folkman, J. et al., J Biol Chem (1992)267(16):10931-10934). Blocking the VEGF-receptor interaction andinhibiting angiogenesis is a proven therapeutic target for cancertreatment (Ferrara, N. et al., Nature (2005) 438(7070):967-974; Tugues,S. et al., Mol Aspects Med (2011) 32(2):88-111). The following studydemonstrates that an abiotic synthetic polymer nanoparticle (NP) withengineered multi point affinity for VEGF₁₆₅, inhibits the VEGF-VEGFRinteraction and downstream VEGF-dependent function in vitro. In vivoadministration of anti-VEGF NPs suppressed tumor growth and normalizedtumor vasculature. Combination therapy with doxorubicin was found toresult in increased doxorubicin concentration in the tumor and dramaticinhibition of tumor growth. This biologically inspired nanoparticleestablishes a new paradigm for inhibiting protein-protein interactionsusing synthetic polymer nanoparticles and points the way to alternative,inexpensive, abiotic angiogenesis inhibitors.

Just as medicinal chemists routinely design and synthesize small drugmolecules that bind to the active site of a target protein, advances inpolymer synthesis, structural biology and nanotechnology have progressedto the point where synthetic polymer nanoparticles (NPs) can be designedwith high affinity and selectivity for a targeted protein. The presentstudy describes an abiotic synthetic polymer nanoparticle that functionsas a protein capture agent, a “plastic antibody”, and its therapeuticapplication in vivo. These results establish the potential forinexpensive synthetic polymer nanoparticles as inhibitors ofprotein-protein interactions that are involved in signal transductionand may point the way to abiotic, cost effective anti-angiogenic agentsfor treatment of certain cancers.

The emergence of protein therapeutics marks an important advance inmodern medicine. Many protein therapeutic agents exploit the selectivityand affinity of antibodies to modulate or inhibit protein function. Thenumber of FDA approved protein drugs and those at various stages ofclinical trials attest to the vitality of the field and is a measure theefficacy of this strategy (Mullard, A., Nat Rev Drug Discov (2013)12(5):329-332). Despite their significant role in contemporary medicine,the costs of discovery and production of humanized antibodies can placea burden on the health care system. It is anticipated that the costs ofthese proteins will be reduced in time making them more widelyavailable. Nevertheless new strategies, particularly those that couldrapidly produce efficacious candidates without the use of livingorganisms and at lower cost, warrant consideration as potentialalternatives. Previous studies have demonstrated that a syntheticpolymer hydrogel nanoparticle (NP), made by copolymerization of monomerscontaining functional groups complimentary to those of a target peptidetoxin melittin, bind the toxin with low nanomolar affinity (Hoshino, Y.et al., J Am Chem Soc (2008) 130(46):15242-15243; Hoshino, Y. et al.,Small (2009) 5(13):1562-1568). In vitro and in vivo studies of theanti-toxin NPs, established a dose dependent inhibition of cytotoxicityproviding the potential for an abiotic treatment of injuries anddiseases caused by peptide toxins (Hoshino, Y. et al., J Am Chem Soc(2010) 132(19):6644-6645; Hoshino, Y. et al., Proc Natl Acad Sci USA(2012) 109(1):33-38). Subsequent studies revealed the NPs sequester andclear the toxin neutralizing its activity (Hoshino, Y. et al., Proc NatlAcad Sci USA (2012) 109(1):33-38; Hu, C. M. et al., Nat Nanotechnol(2013) 8(5):336-340; Smith, M. H. et al., Macromolecules (2011)44(20):8154-8160). It has also been established that NPs can beformulated to recognize and bind to a specific domain of large proteins(IgG, lysozyme) (Lee, S. H. et al., J Am Chem Soc. (2012)134(38):15765-15772; Yoshimatsu, K. et al., Angew Chem Int Ed Engl(2012) 51(10):2405-2408). These results establish the efficacy ofsynthetic polymer NPs both in vitro and in vivo settings and callattention to the potential for their use as alternative, stable proteinaffinity ligands for diagnostics, research tools in molecular biology,drug delivery, disease therapy, and as antidotes for toxins and viruses(Hoshino, Y. et al., Proc Natl Acad Sci USA (2012) 109(1):33-38; Hu, C.M. et al., Nat Nanotechnol (2013) 8(5):336-340).

The following study describes a synthetic polymer hydrogel nanoparticleengineered to bind to a vascular endothelial growth factor (VEGF) andits potential for anti-angiogenic therapy. Angiogenesis is induced byseveral growth factors, most importantly VEGF₁₆₅, a 165 amino acidprotein (39.2 kDa, pI=7.6). Inhibition of the function of VEGF₁₆₅ is anattractive strategy for anti-cancer therapy because tumors can beinduced to apoptosis by reducing or shutting down the blood supply ofnutrients and oxygen (Cao, Y., Semin Cancer Biol (2004) 14(2):139-145).An important example is Avastin® (bevacizumab), an anti-VEGF monoclonalantibody approved by the FDA in 2004.

Avastin® targets the VEGF receptor-binding domain and is proposed tocompetitively inhibit the binding of VEGF to its receptors (VEGFR-1 and2). VEGF₁₆₅ and VEGFR-2 binding is attributed in part to hydrophobicinteractions including Phe17, Ile43, Ile46, Ile83 and Pro85 of VEGF-A15.It is also known that VEGF₁₆₅ has a heparin-binding domain. Heparin, ahighly sulfated carbohydrate comprised of N-acetylglucosamine units,binds to VEGF₁₆₅ through Arg 124, 145, 149 and 159 in the VEGF₁₆₅sequence 16. It has been proposed that the heparin-binding domainassists the binding of VEGF₁₆₅ to VEGFR-217. Here, synthetic polymer NPscontaining both hydrophobic and negatively charged groups are optimizedfor affinity to VEGF₁₆₅. As with related antibody strategies, NP bindingto VEGF₁₆₅ could inhibit its function.

The materials and methods used in these experiments are now described.

Preparation of NPs

NPs were synthesized of by free-radical copolymerization ofN-isopropylacrylamide (NIPAm) cross-linked with 2 mol %N,N′-methylenebisacrylamide (Bis). N-tert-butylacrylamide (TBAm) and3-sulfo-N-acetylglucosamines (3S), 4-sulfo-N-acetylglucosamines (4S),6-sulfo-N-acetylglucosamines (6S) or 3,4,6-sulfo-N-acetylglucosamines(3,4,6S) were used as hydrophobic and negatively charged functionalmonomers. The polymerization was carried out at 65° C. for 3 h under anitrogen atmosphere. The polymerized solutions were purified bydialysis.

Characterization of NPs

The hydrodynamic diameter of NPs was determined in aqueous solution bydynamic light scattering (DLS) (Zetasizer Nano ZS).

Quantification of GlcNAc monomers in Nps by ¹H-NMR

In order to determine the ratio of TBAm, NIPAm, and GlcNAc in thepolymer, ¹H NMR spectroscopy was utilized using an acquisition time of30 seconds, respectively.

Quartz Crystal Microbalance (QCM) Analysis

An Affinix Q⁴ QCM instrument (Initium Co. Ltd., Tokyo, Japan) was usedto quantify interactions between the NPs and proteins.

Experimental Animals

Five-week-old BALB/c male mice were purchased from Japan SLC Inc.(Shizuoka, Japan). The animals were cared for according to the AnimalFacility Guidelines of the University of Shizuoka. All animalexperiments were approved by the Animal and Ethics Review Committee ofthe University of Shizuoka.

Histological Assessment of Liver

Five-week-old BALB/c-male mice (n=3) were intravenously injected withNP11 (40 mg/kg). Two weeks after the injection, the liver sections werestained with hematoxylin and eosin. Photographs were taken with anOlympus IX71 microscope.

Measurement of TNF-α and IL-12

Five-week-old BALB/c-male mice (n=4) were intravenously injected withPBS (for negative control), NP11 (40 mg/kg) or lipopolysaccharide (LPS).The serum was collected at 1, 6 and 12 h after the injection. TNF-α andIL-12 levels in the serum were determined using a specific ELISA kit(Mouse TNF-α ELISA kit, R&D systems, MN, U.S.A. and Mouse IL-12 ELISAKit, BD Biosciences, CA, U.S.A.).

Therapeutic Experiment

Colon26 NL-17 cells (1.0×106 cells/mouse) were subcutaneously inoculatedinto the posterior flank of 5-week-old BALB/c male mice. Five days afterthe tumor implantation, these mice were injected with PBS or NPs (5, 10,20 or 40 mg/kg, 200 μL/mouse) at day 5, 7, 9 and 11 after the tumorinoculation. For combination therapy, the mice were injected with NPs(20 or 40 mg/kg, 200 μL/mouse) at day 5, 7, 9 and 11, and doxorubicin(2.5 or 5 mg/kg, 200 μL/mouse) at day 6, 8, 10 and 12 after the tumorinoculation. The size of the tumors and the body weight of each mousewere monitored. Calculation of the tumor volume was performed using theformula 0.4×(a×b2).

Tumor Perfusion Analysis

To analyze the perfusion efficiency, the mice were intravenouslyinjected with 100 μl of 1 mg/ml biotinylated lycopersicon esculentum(tomato) lectin (Vector laboratories) 24 h after the final NP11injection. The lectin was circulated for 10 min and mice were perfusedwith 1% paraformaldehyde in PBS before tumors were collected. Tumorsections were stained with Alexa594-conjugated streptavidin andFITC-conjugated anti-CD31 antibody to identify perfused and totalvessels, respectively.

Measurement of Dox in Tumor

Tumor-implanted mice were injected with NPs (40 mg/kg, 200 μL/mouse) atday 5, 7, 9 and 11, and doxorubicin (5 mg/kg, 200 μL/mouse) at day 6, 8,10 and 12 after the tumor inoculation. Four hours after the final Doxinjection, the tumors were homogenized in 10 volumes (w/v) of 10 mMphosphate buffer (pH 7.8). Then, the Dox in the tumor was extracted bychloroform:methanol (4:1, v/v). The organic layer was completely dry andre-suspended with 1% formic acid containing H₂O:MeOH (1:1, v/v).

Measurement of Dox

The UPLC-ESI-TOF-MS system consisted of an ACQUITY™ ultra-performancelipid chromatography and a Micromass LCT Premier™ XE mass spectrometer(high-sensitivity orthogonal time-of-flight instrument; Waters, Milford,Mass., USA).

Statistical Analysis

Differences in a group were evaluated by an analysis of variance (ANOVA)with the Tukey post hoc test.

The results are now described.

Tumor Growth Inhibition by Combination Therapy of NPs and Dox

In vivo anti-angiogenic activity was examined using nanoparticle NP11,which incorporates 1.7% of the 3,4,6S-GlcNAc monomer. In preliminarystudies subcutaneously tumor-implanted mice were used to measure thebiodistribution of ¹⁴C-labeled NP11 at 30 min or 1 h (FIG. 16A). NP11accumulated mainly in the liver, and did not accumulate significantly inother organs and in the bloodstream. Histological assessment of theliver indicates that there is no significant difference between PBS andNP11 injection. Furthermore, acute inflammatory cytokines, TNF-α andIL-12, were not significantly upregulated in the plasma by the presenceof NP11. Approximately 15% of the injected NP11 remained in the liverand 5% in the kidney 2 weeks after the injection. However, more than 97%of NPs were eliminated from the body at 4 weeks (FIG. 16B). Theseresults indicate that within the therapeutic window of the in vivoexperiments, complications arising from immunogenicity and toxicity ofNP11 should not be problematic.

To evaluate whether NP11 inhibits tumor growth in vivo by inhibition ofangiogenesis, tumor implanted mice were injected with NP11 (5, 10, 20,40 mg/kg). NP11 significantly inhibited tumor growth without significantbody weight changes compared to PBS treatment (FIG. 16C). Only a few %of NP11 exists in the tumor 1 h after intravenous injection. A possibleexplanation is that NP11 interacts with VEGF₁₆₅ in the vicinity of thetumor where it is sequestered and removed. In addition, the small amountof NP11 that remains in the vicinity of the tumor may continue to clearVEGF₁₆₅ secreted from the tumor.

An interesting new concept has emerged suggesting that apart frominhibiting new vessel formation, anti-angiogenic therapy may normalizethe established tumor vasculature and increase anticancer drugconcentration in the tumor (Park, J. E. et al., Mol Biol Cell (1993)4(12):1317-1326; Jain, R. K., Science (2005) 307(5706):58-62; Greenberg,J. I. et al., Nature (2008) 456(7223):809-813; Wildiers, H. et al. Br JCancer (2003) 88(12):1979-1986; Jain, R. K., Nat Rev Cancer (2008)8(4):309-316). Consistent with this concept, anti-VEGF medicines arefrequently used in combination with anti-cancer drugs. This combinationtherapy often induces a synergistic effect (Singleton, P. A. et al., MolCancer Ther (2008) 7(6):1669-1679). To establish if the NPs also inducea synergistic effect, NP11 (20 or 40 mg/kg) and doxorubicin (Dox, 2.5 or5 mg/kg), an anti-cancer drug, were administered into tumor-implantedmice. Tumor growth was significantly inhibited at Dox concentrationlevels of 2.5 or 5 mg/kg in combination therapy compared with NP11 orDox injection alone (FIG. 16D, FIG. 16E). In addition, when therapy wasinitiated with mice using NP11 (40 mg/kg) and Dox (5 mg/kg), theimplanted tumor size did not increase in size until 6 days after thefinal injection. Some reduction in body weight was noted by combinationtherapy, which could be due to side effects triggered from the Doxinjection.

Blood perfusion efficiency was determined following NP11 treatment byintravenous injection of biotin-labeled lectin (before preparation oftumor section) and CD31 (after preparation of tumor section) staining.CD31 staining reveals all blood vessels while biotin-labeled lectinbinds to only perfused endothelial cells (FIG. 16F). Tumors treated withPBS show significant numbers of endothelial cells that were not mergedwith biotin-labeled lectin (CD31 positive and lectin negative). Incontrast, NP11 treated tumors show that every endothelial cell wasmerged with biotin-labeled lectin (CD31 and lectin positive). The tumorvessel perfusion and microvessel density after the NP11 treatment weresignificantly reduced compared with non-treated tumor. In addition, theconcentration of Dox in the tumor was significantly increased by theNP11 injection (FIG. 16G). These results indicate that NP11 disruptednon-effective blood vessel formation and normalized tumor vasculature,and increased Dox accumulation in the tumor.

In summary, a novel abiotic synthetic polymer NP was developed withaffinity for VEGF₁₆₅. The NP targeted the heparin-binding domain thruthe 3,4,6 trisulfate N-acetylglucosamine. Hydrophobic groups on the NPwere also important for its interaction with hydrophobic domains on thesurface of VEGF. Optimized non-toxic NPs efficiently inhibitedVEGF-VEGFR interactions in vitro and in vivo resulting in suppression oftumor growth. The concept of a synthetic polymer NP interacting with alarge area of target protein thru complementary interactions andinhibiting its function should provide strong impetus for efforts toengineer novel bioactive agents for biomedical applications. Theseabiotic materials have the potential to be used as inexpensive andstable functional materials for applications that include diagnostics,research tools in molecular biology, or for disease therapy and may verywell point the way to a novel, abiotic, cost effective anti-angiogenicagent for treatment of certain cancers.

The disclosures of each and every patent, patent application, andpublication cited herein are hereby incorporated herein by reference intheir entirety. While this invention has been disclosed with referenceto specific embodiments, it is apparent that other embodiments andvariations of this invention may be devised by others skilled in the artwithout departing from the true spirit and scope of the invention. Theappended claims are intended to be construed to include all suchembodiments and equivalent variations.

1. An abiotic, synthetic polymer composition, comprising:N-isopropylacrylamide (NIPAm); N-tert-butylacrylamide (TBAm);N,N′-methylenebisacrylamide (Bis); and a sulfated monomer.
 2. Thecomposition of claim 1, wherein the composition has affinity to vascularendothelial growth factor (VEGF).
 3. The composition of claim 1, whereinthe sulfated monomer is a N-acetylglucosamine (GlcNAc) selected from thegroup consisting of 3S-GlcNAc, 4S-GlcNAc, 6S-GlcNAc, and 3,4,6S-GlcNAc.4-5. (canceled)
 6. The composition of claim 1, wherein the compositioncomprises between 30% and 70% NIPAm.
 7. The composition of claim 1,wherein the composition comprises between 30% and 50%. TBAm.
 8. Thecomposition of claim 1, wherein the composition comprises between 0% and10% Bis.
 9. The composition of claim 3, wherein the compositioncomprises between 1% and 20% GlcNAc.
 10. (canceled)
 11. The compositionof claim 1, wherein the composition comprises 56.3% NIPAm, 40% TBAm, 2%Bis, and 1.7% 3,4,6S-GlcNAc.
 12. The composition of claim 1, wherein thecomposition is a nanoparticle.
 13. The composition of claim 1, whereinthe composition further comprises at least one therapeutic agent. 14-27.(canceled)
 28. A method of inhibiting angiogenesis in a subject,comprising administering to a subject a therapeutically effective amountof an abiotic, synthetic polymer composition having affinity to VEGF.29. The method of claim 28, wherein the composition comprisesN-isopropylacrylamide (NIPAm), N-tert-butylacrylamide (TBAm),N,N′-methylenebisacrylamide (Bis), and a sulfated monomer.
 30. Themethod of claim 29, wherein the sulfated monomer is a Nacetylglucosamine (GlcNAc) selected from the group consisting of3S-GlcNAc, 4S-GlcNAc, 6S-GlcNAc, and 3,4,6S-GlcNAc. 31-37. (canceled)38. The method of claim 29, wherein the composition comprises 56.3%NIPAm, 40% TBAm, 2% Bis, and 1.7% 3,4,6S-GlcNAc.
 39. The method of claim28, wherein the composition is a nanoparticle.
 40. The method of claim28, wherein the method is capable of treating cancer.
 41. The method ofclaim 28, wherein the composition is administered with a therapeuticagent.
 42. The method of claim 41, wherein the therapeutic agent is theanti-tumor agent doxorubicin.
 43. A method of detecting cancer in asubject, comprising the steps of: acquiring a biological sample from thesubject; and quantifying the amount of VEGF present in the biologicalsample using an abiotic, synthetic polymer composition having affinityto VEGF.
 44. The method of claim 43, wherein the composition comprisesN-isopropylacrylamide (NIPAm), N-tert-butylacrylamide (TBAm),N,N′-methylenebisacrylamide (Bis), and a sulfated monomer. 45.(canceled)